Fix megacheck issue unused code.

I removed some code, and commented out other one.

See,
$ gometalinter --vendor --disable-all --disable=gotype --enable=megacheck --deadline 6m ./... | grep unused
pkg/api/avatar/avatar.go:100:26⚠️ func (*CacheServer).mustInt is unused (U1000) (megacheck)
pkg/api/folder_test.go:136:6⚠️ func callGetFolderByUID is unused (U1000) (megacheck)
pkg/api/folder_test.go:141:6⚠️ func callDeleteFolder is unused (U1000) (megacheck)
pkg/api/live/hub.go:40:15⚠️ func (*hub).removeConnection is unused (U1000) (megacheck)
pkg/components/imguploader/azureblobuploader.go:130:5⚠️ var client is unused (U1000) (megacheck)
pkg/middleware/middleware_test.go:438:28⚠️ func (*scenarioContext).withInvalidApiKey is unused (U1000) (megacheck)
pkg/services/alerting/ticker.go:40:18⚠️ func (*Ticker).updateOffset is unused (U1000) (megacheck)
pkg/services/notifications/notifications_test.go:12:6⚠️ type testTriggeredAlert is unused (U1000) (megacheck)
pkg/services/sqlstore/dashboard_service_integration_test.go:935:6⚠️ type scenarioContext is unused (U1000) (megacheck)
pkg/services/sqlstore/dashboard_service_integration_test.go:939:6⚠️ type scenarioFunc is unused (U1000) (megacheck)
pkg/services/sqlstore/dashboard_service_integration_test.go:941:6⚠️ func dashboardGuardianScenario is unused (U1000) (megacheck)
pkg/services/sqlstore/transactions_test.go:13:6⚠️ type testQuery is unused (U1000) (megacheck)

pkg/api/avatar/avatar.go

@@ -97,15 +97,6 @@ type CacheServer struct {
 	cache    *gocache.Cache
 }
 
-func (this *CacheServer) mustInt(r *http.Request, defaultValue int, keys ...string) (v int) {
-	for _, k := range keys {
-		if _, err := fmt.Sscanf(r.FormValue(k), "%d", &v); err == nil {
-			defaultValue = v
-		}
-	}
-	return defaultValue
-}
-
 func (this *CacheServer) Handler(ctx *macaron.Context) {
 	urlPath := ctx.Req.URL.Path
 	hash := urlPath[strings.LastIndex(urlPath, "/")+1:]