compositor: Drop error trap

Code underneath seems to handle errors properly, and this is apparently
here to save a few XSync()s on X11. Just drop this windowing dependent
bit to make things cleaner.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/420

src/compositor/compositor.c

@@ -692,11 +692,8 @@ meta_compositor_add_window (MetaCompositor    *compositor,
 {
   MetaWindowActor *window_actor;
   ClutterActor *window_group;
-  MetaDisplay *display = compositor->display;
   GType window_actor_type = G_TYPE_INVALID;
 
-  meta_x11_error_trap_push (display->x11_display);
-
   switch (window->client_type)
     {
     case META_WINDOW_CLIENT_TYPE_X11:
@@ -724,8 +721,6 @@ meta_compositor_add_window (MetaCompositor    *compositor,
    */
   compositor->windows = g_list_append (compositor->windows, window_actor);
   sync_actor_stacking (compositor);
-
-  meta_x11_error_trap_pop (display->x11_display);
 }
 
 void