[mutter/wayland] Revert "wayland-surface: Allow extension resources to be double-destroyed"

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

commit a8632c2546f2e18a3a7cec49b25b804cc242ea01
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Tue Nov 19 23:32:50 2013 -0500

    Revert "wayland-surface: Allow extension resources to be double-destroyed"
    
    This reverts commit 2ebecc5370eb61668feff2fd8742891ca40f30fc.

 src/wayland/meta-wayland-surface.c |    4 ----
 1 files changed, 0 insertions(+), 4 deletions(-)
---
diff --git a/src/wayland/meta-wayland-surface.c b/src/wayland/meta-wayland-surface.c
index 78f54a2..f208da8 100644
--- a/src/wayland/meta-wayland-surface.c
+++ b/src/wayland/meta-wayland-surface.c
@@ -470,10 +470,6 @@ static void
 destroy_surface_extension (struct wl_resource *resource)
 {
   MetaWaylandSurfaceExtension *extension = wl_resource_get_user_data (resource);
-
-  if (extension->resource == NULL)
-    return;
-
   wl_list_remove (&extension->surface_destroy_listener.link);
   extension->surface_destroy_listener.notify = NULL;
   extension->resource = NULL;