[mutter] meta-surface-actor-x11: Detatch the pixmap in window_decorated_notify

[Adel Gadllah <agadllah src gnome org>]

commit a1165093019482e925b03aa4f76b61f9072ed45b
Author: Adel Gadllah <adel gadllah gmail com>
Date:   Wed Oct 8 23:07:41 2014 +0200

    meta-surface-actor-x11: Detatch the pixmap in window_decorated_notify
    
    The window can change its decoration without changing its size.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=738146
    
    Found by Jasper St. Pierre <jstpierre mecheye net>

 src/compositor/meta-surface-actor-x11.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/src/compositor/meta-surface-actor-x11.c b/src/compositor/meta-surface-actor-x11.c
index 3563f96..8af5ca2 100644
--- a/src/compositor/meta-surface-actor-x11.c
+++ b/src/compositor/meta-surface-actor-x11.c
@@ -383,6 +383,7 @@ window_decorated_notify (MetaWindow *window,
 {
   MetaSurfaceActorX11 *self = META_SURFACE_ACTOR_X11 (user_data);
 
+  detach_pixmap (self);
   free_damage (self);
   create_damage (self);
 }