Fix MythVideo general settings page not working

How long that one has been broken ???

The new MythUI screen is always on top, so it must be hidden when starting on old Qt screen…
Hopefully there are no more like this

mythtv/programs/mythfrontend/main.cpp

@@ -810,7 +810,7 @@ static void TVMenuCallback(void *data, QString &selection)
     (void)data;
     QString sel = selection.toLower();
 
-    if (sel.startsWith("settings "))
+    if (sel.startsWith("settings ") || sel == "video_settings_general")
     {
         GetMythUI()->AddCurrentLocation("Setup");
         gCoreContext->ActivateSettingsCache(false);