[mutter] display: Destroy compositor using g_clear_pointer

[Jonas Ådahl <jadahl src gnome org>]

commit 93c7d571afcd24e3bb3d12dadd25dee8a96c3d38
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Tue Apr 30 18:47:42 2019 -0500

    display: Destroy compositor using g_clear_pointer
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/385

 src/core/display.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)
---
diff --git a/src/core/display.c b/src/core/display.c
index 395b541bb..fb4b127f5 100644
--- a/src/core/display.c
+++ b/src/core/display.c
@@ -975,8 +975,7 @@ meta_display_close (MetaDisplay *display,
   /* Stop caring about events */
   meta_display_free_events (display);
 
-  if (display->compositor)
-    meta_compositor_destroy (display->compositor);
+  g_clear_pointer (&display->compositor, meta_compositor_destroy);
 
   meta_display_shutdown_x11 (display);