Disable "Game Saved" text box in custommode

Also, use inspecial() instead of writing out each part of the
conditional separately. This just basically adds the insecretlab
conditional to the if-statement, which shouldn't be a big deal.

desktop_version/src/Game.cpp

@@ -1924,7 +1924,7 @@ void Game::updatestate()
 
         case 2000:
             //Game Saved!
-            if (intimetrial || nodeathmode || inintermission)
+            if (inspecial() || map.custommode)
             {
                 state = 0;
             }