Simplify error returns (gosimple)

This fixes:
pkg/api/avatar/avatar.go:261:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/log/file.go:102:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/metrics/graphitebridge/graphite.go:298:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/provisioning/provisioning.go:23:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/alert_notification.go:27:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/alert_notification.go:27:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/annotation.go:105:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/annotation.go:105:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard.go:351:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard.go:435:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard_acl.go:38:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/dashboard_acl.go:38:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/stats.go:22:2: 'if err != nil { return err }; return err' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/team.go:213:2: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:256:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:256:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:274:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:274:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:482:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)
pkg/services/sqlstore/user.go:482:3: 'if err != nil { return err }; return nil' can be simplified to 'return err' (S1013)

pkg/services/provisioning/provisioning.go

@@ -20,11 +20,7 @@ func Init(ctx context.Context, homePath string, cfg *ini.File) error {
 
 	dashboardPath := path.Join(provisioningPath, "dashboards")
 	_, err := dashboards.Provision(ctx, dashboardPath)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 func makeAbsolute(path string, root string) string {