[mutter] cogl/framebuffer: Clean up cleanup function

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit e7ac3e2715cfa274c2a28554df0ef042bdf87e4b
Author: Jonas Ådahl <jadahl gmail com>
Date:   Tue Oct 13 09:19:00 2020 +0200

    cogl/framebuffer: Clean up cleanup function
    
    Use cogl_clear_object() and g_clear_pointer() helpers.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1496

 cogl/cogl/cogl-framebuffer.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)
---
diff --git a/cogl/cogl/cogl-framebuffer.c b/cogl/cogl/cogl-framebuffer.c
index b89f84fa47..0bc734ecb2 100644
--- a/cogl/cogl/cogl-framebuffer.c
+++ b/cogl/cogl/cogl-framebuffer.c
@@ -283,15 +283,11 @@ _cogl_framebuffer_free (CoglFramebuffer *framebuffer)
 
   _cogl_fence_cancel_fences_for_framebuffer (framebuffer);
 
-  _cogl_clip_stack_unref (priv->clip_stack);
 
-  cogl_object_unref (priv->modelview_stack);
-  priv->modelview_stack = NULL;
-
-  cogl_object_unref (priv->projection_stack);
-  priv->projection_stack = NULL;
-
-  cogl_object_unref (priv->journal);
+  g_clear_pointer (&priv->clip_stack, _cogl_clip_stack_unref);
+  cogl_clear_object (&priv->modelview_stack);
+  cogl_clear_object (&priv->projection_stack);
+  cogl_clear_object (&priv->journal);
 
   ctx->framebuffers = g_list_remove (ctx->framebuffers, framebuffer);