[gtk+/gtk-2-24] Fix gtk-demo drawingarea example

[Matthias Clasen <matthiasc src gnome org>]

commit 4fc684943b3b8969b7ac9ce9fa8dfe7312c76ebc
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Nov 30 12:09:21 2011 -0500

    Fix gtk-demo drawingarea example
    
    Patch by Martin Schlemmer, bug 665011.

 demos/gtk-demo/drawingarea.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/demos/gtk-demo/drawingarea.c b/demos/gtk-demo/drawingarea.c
index 84f3958..1b1c9bb 100644
--- a/demos/gtk-demo/drawingarea.c
+++ b/demos/gtk-demo/drawingarea.c
@@ -205,7 +205,7 @@ close_window (void)
   window = NULL;
 
   if (surface)
-    g_object_unref (surface);
+    cairo_surface_destroy (surface);
   surface = NULL;
 }