#2630 fix wrong user avatar link in webhook

Was using the wrong method and now uses the method which checks if
the avatar link is relative or not.

models/action.go

@@ -498,7 +498,7 @@ func CommitRepoAction(
 	payloadSender := &api.PayloadUser{
 		UserName:  pusher.Name,
 		ID:        pusher.Id,
-		AvatarUrl: setting.AppUrl + pusher.RelAvatarLink(),
+		AvatarUrl: pusher.AvatarLink(),
 	}
 
 	switch opType {