[mutter] keybindings: Fix backend check in change_keygrabs

[Jasper St. Pierre <jstpierre src gnome org>]

commit 2a3d4b62a72eda7977c97c0bf94c346ed2f7153f
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Mon Jul 14 15:30:03 2014 -0400

    keybindings: Fix backend check in change_keygrabs
    
    We really can't do this unless the backend X server is the same as the
    frontend X server, as we pass a frontend XID to the backend, which is
    only the case when we're not a Wayland compositor.

 src/core/keybindings.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/src/core/keybindings.c b/src/core/keybindings.c
index 50fdf12..09d95d5 100644
--- a/src/core/keybindings.c
+++ b/src/core/keybindings.c
@@ -1194,9 +1194,8 @@ meta_window_change_keygrabs (MetaWindow *window,
 void
 meta_window_grab_keys (MetaWindow  *window)
 {
-  MetaBackend *backend = meta_get_backend ();
-
-  if (!META_IS_BACKEND_X11 (backend))
+  /* Under Wayland, we don't need to grab at all. */
+  if (meta_is_wayland_compositor ())
     return;
 
   if (window->all_keys_grabbed)