Fix kludge_ingametemp being assigned after menu creation

While working on #535, I noticed this bug.

When going to Graphic Options or Game Options from the pause menu,
kludge_ingametemp was intended to save the current menu stack frame
BEFORE either of those menus got created. However, it was actually
assigned afterwards, meaning kludge_ingametemp would always be either
Menu::graphicoptions or Menu::options.

This meant that the returntomenu() in returntopausemenu() would always
attempt to return to the current in-game menu, and seeing as it's the
same menu, would re-create the menu, instead of returning to the
previous menu before it.

This patch also fixes a potential source of a trivial memory leak, if
someone were to keep entering and exiting Graphic Options or Game
Options from the pause menu. It would keep piling up duplicate Graphic
Options or Game Options stack frames, which would never get removed.
However, they do get removed when you exit to the menu properly, by
returntomenu() again, so this doesn't seem like that serious of an
issue, but it's still good to fix.

desktop_version/src/Input.cpp

@@ -2389,6 +2389,10 @@ void mapmenuactionpress()
         game.gamestate = TITLEMODE;
         graphics.flipmode = false;
         game.ingame_titlemode = true;
+
+        // Set this before we create the menu
+        game.kludge_ingametemp = game.currentmenuname;
+
         if (game.menupage == 32)
         {
             game.createmenu(Menu::graphicoptions);
@@ -2397,7 +2401,6 @@ void mapmenuactionpress()
         {
             game.createmenu(Menu::options);
         }
-        game.kludge_ingametemp = game.currentmenuname;
 
         map.nexttowercolour();