Fix -playmusic command line option not working

There's a bug where playtesting from Ved doesn't properly play the music
of the level, due to no fault with Ved.

This was because the music was being faded out by
scriptclass::startgamemode() case 23 after main() called music.play().
To fix this, just call music.play() when all the other variables are
being set in Game::customloadquick().

desktop_version/src/main.cpp

@@ -353,8 +353,8 @@ int main(int argc, char *argv[])
             game.playrx = saverx;
             game.playry = savery;
             game.playgc = savegc;
+            game.playmusic = savemusic;
             game.cliplaytest = true;
-            music.play(savemusic);
             script.startgamemode(23);
         } else {
             script.startgamemode(22);