This commit fixes the following golint warnings:
pkg/api/avatar/avatar.go:229:12: should omit type *http.Client from declaration of var client; it will be inferred from the right-hand side
pkg/login/brute_force_login_protection.go:13:26: should omit type time.Duration from declaration of var loginAttemptsWindow; it will be inferred from the right-hand side
pkg/metrics/graphitebridge/graphite.go:58:26: should omit type []string from declaration of var metricCategoryPrefix; it will be inferred from the right-hand side
pkg/metrics/graphitebridge/graphite.go:69:22: should omit type []string from declaration of var trimMetricPrefix; it will be inferred from the right-hand side
pkg/models/alert.go:37:36: should omit type error from declaration of var ErrCannotChangeStateOnPausedAlert; it will be inferred from the right-hand side
pkg/models/alert.go:38:36: should omit type error from declaration of var ErrRequiresNewState; it will be inferred from the right-hand side
pkg/models/datasource.go:61:28: should omit type map[string]bool from declaration of var knownDatasourcePlugins; it will be inferred from the right-hand side
pkg/plugins/update_checker.go:16:13: should omit type http.Client from declaration of var httpClient; it will be inferred from the right-hand side
pkg/services/alerting/engine.go:103:24: should omit type time.Duration from declaration of var unfinishedWorkTimeout; it will be inferred from the right-hand side
pkg/services/alerting/engine.go:105:19: should omit type time.Duration from declaration of var alertTimeout; it will be inferred from the right-hand side
pkg/services/alerting/engine.go:106:19: should omit type int from declaration of var alertMaxAttempts; it will be inferred from the right-hand side
pkg/services/alerting/notifier.go:143:23: should omit type map[string]*NotifierPlugin from declaration of var notifierFactories; it will be inferred from the right-hand side
pkg/services/alerting/rule.go:136:24: should omit type map[string]ConditionFactory from declaration of var conditionFactories; it will be inferred from the right-hand side
pkg/services/alerting/conditions/evaluator.go:12:15: should omit type []string from declaration of var defaultTypes; it will be inferred from the right-hand side
pkg/services/alerting/conditions/evaluator.go:13:15: should omit type []string from declaration of var rangedTypes; it will be inferred from the right-hand side
pkg/services/alerting/notifiers/opsgenie.go:44:19: should omit type string from declaration of var opsgenieAlertURL; it will be inferred from the right-hand side
pkg/services/alerting/notifiers/pagerduty.go:43:23: should omit type string from declaration of var pagerdutyEventApiUrl; it will be inferred from the right-hand side
pkg/services/alerting/notifiers/telegram.go:21:17: should omit type string from declaration of var telegramApiUrl; it will be inferred from the right-hand side
pkg/services/provisioning/dashboards/config_reader_test.go:11:24: should omit type string from declaration of var simpleDashboardConfig; it will be inferred from the right-hand side
pkg/services/provisioning/dashboards/config_reader_test.go:12:24: should omit type string from declaration of var oldVersion; it will be inferred from the right-hand side
pkg/services/provisioning/dashboards/config_reader_test.go:13:24: should omit type string from declaration of var brokenConfigs; it will be inferred from the right-hand side
pkg/services/provisioning/dashboards/file_reader.go:22:30: should omit type time.Duration from declaration of var checkDiskForChangesInterval; it will be inferred from the right-hand side
pkg/services/provisioning/dashboards/file_reader.go:24:23: should omit type error from declaration of var ErrFolderNameMissing; it will be inferred from the right-hand side
pkg/services/provisioning/datasources/config_reader_test.go:15:34: should omit type string from declaration of var twoDatasourcesConfig; it will be inferred from the right-hand side
pkg/services/provisioning/datasources/config_reader_test.go:16:34: should omit type string from declaration of var twoDatasourcesConfigPurgeOthers; it will be inferred from the right-hand side
pkg/services/provisioning/datasources/config_reader_test.go:17:34: should omit type string from declaration of var doubleDatasourcesConfig; it will be inferred from the right-hand side
pkg/services/provisioning/datasources/config_reader_test.go:18:34: should omit type string from declaration of var allProperties; it will be inferred from the right-hand side
pkg/services/provisioning/datasources/config_reader_test.go:19:34: should omit type string from declaration of var versionZero; it will be inferred from the right-hand side
pkg/services/provisioning/datasources/config_reader_test.go:20:34: should omit type string from declaration of var brokenYaml; it will be inferred from the right-hand side
pkg/services/sqlstore/stats.go:16:25: should omit type time.Duration from declaration of var activeUserTimeLimit; it will be inferred from the right-hand side
pkg/services/sqlstore/migrator/mysql_dialect.go:69:14: should omit type bool from declaration of var hasLen1; it will be inferred from the right-hand side
pkg/services/sqlstore/migrator/mysql_dialect.go:70:14: should omit type bool from declaration of var hasLen2; it will be inferred from the right-hand side
pkg/services/sqlstore/migrator/postgres_dialect.go:95:14: should omit type bool from declaration of var hasLen1; it will be inferred from the right-hand side
pkg/services/sqlstore/migrator/postgres_dialect.go:96:14: should omit type bool from declaration of var hasLen2; it will be inferred from the right-hand side
pkg/setting/setting.go:42:15: should omit type string from declaration of var Env; it will be inferred from the right-hand side
pkg/setting/setting.go:161:18: should omit type bool from declaration of var LdapAllowSignup; it will be inferred from the right-hand side
pkg/setting/setting.go:473:30: should omit type bool from declaration of var skipStaticRootValidation; it will be inferred from the right-hand side
pkg/tsdb/interval.go:14:21: should omit type time.Duration from declaration of var defaultMinInterval; it will be inferred from the right-hand side
pkg/tsdb/interval.go:15:21: should omit type time.Duration from declaration of var year; it will be inferred from the right-hand side
pkg/tsdb/interval.go:16:21: should omit type time.Duration from declaration of var day; it will be inferred from the right-hand side
pkg/tsdb/cloudwatch/credentials.go:26:24: should omit type map[string]cache from declaration of var awsCredentialCache; it will be inferred from the right-hand side
pkg/tsdb/influxdb/query.go:15:27: should omit type *regexp.Regexp from declaration of var regexpOperatorPattern; it will be inferred from the right-hand side
pkg/tsdb/influxdb/query.go:16:27: should omit type *regexp.Regexp from declaration of var regexpMeasurementPattern; it will be inferred from the right-hand side
pkg/tsdb/mssql/mssql_test.go:25:14: should omit type string from declaration of var serverIP; it will be inferred from the right-hand side
The datasource uses the default region in the query if the region
is "" in the settings. However setting the region to an empty string
is almost impossible and rendered incorrectly.
This commit introduces a special value "default" for region which
is shown in the drop down and is translated to the default region
of the data source when performing queries.
