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

* fix races

* revert unintentional change

* fix test as intended

api4/webhook.go

@@ -8,15 +8,12 @@ import (
 	"net/http"
 	"strings"
 
-	l4g "github.com/alecthomas/log4go"
 	"github.com/gorilla/mux"
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/utils"
 )
 
 func (api *API) InitWebhook() {
-	l4g.Debug(utils.T("api.webhook.init.debug"))
-
 	api.BaseRoutes.IncomingHooks.Handle("", api.ApiSessionRequired(createIncomingHook)).Methods("POST")
 	api.BaseRoutes.IncomingHooks.Handle("", api.ApiSessionRequired(getIncomingHooks)).Methods("GET")
 	api.BaseRoutes.IncomingHook.Handle("", api.ApiSessionRequired(getIncomingHook)).Methods("GET")