Reduce logging data races, fix MySQL test race condition (#7994)

* fix races

* revert unintentional change

* fix test as intended

api4/file.go

@@ -9,7 +9,6 @@ import (
 	"strconv"
 	"strings"
 
-	l4g "github.com/alecthomas/log4go"
 	"github.com/mattermost/mattermost-server/app"
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/utils"
@@ -44,8 +43,6 @@ var MEDIA_CONTENT_TYPES = [...]string{
 }
 
 func (api *API) InitFile() {
-	l4g.Debug(utils.T("api.file.init.debug"))
-
 	api.BaseRoutes.Files.Handle("", api.ApiSessionRequired(uploadFile)).Methods("POST")
 	api.BaseRoutes.File.Handle("", api.ApiSessionRequiredTrustRequester(getFile)).Methods("GET")
 	api.BaseRoutes.File.Handle("/thumbnail", api.ApiSessionRequiredTrustRequester(getFileThumbnail)).Methods("GET")