[glade/gbinding] Add forgotten NULL check to glade_binding_set_source()

[Denis Washington <denisw src gnome org>]

commit 51824a0410023950e40512b1525a5446bc886447
Author: Denis Washington <denisw src gnome org>
Date:   Fri Jun 10 14:36:29 2011 +0200

    Add forgotten NULL check to glade_binding_set_source()

 gladeui/glade-binding.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/gladeui/glade-binding.c b/gladeui/glade-binding.c
index 2f4fb16..8398ef9 100644
--- a/gladeui/glade-binding.c
+++ b/gladeui/glade-binding.c
@@ -242,11 +242,11 @@ glade_binding_set_source (GladeBinding  *binding,
   if (priv->source)
     g_object_remove_weak_pointer (G_OBJECT (priv->source),
                                   (gpointer *) &priv->source);
+  if (source)
+    g_object_add_weak_pointer (G_OBJECT (source),
+                               (gpointer *) &priv->source);
 
   priv->source = source;
-  g_object_add_weak_pointer (G_OBJECT (priv->source),
-                             (gpointer *) &priv->source);
-  
   glade_binding_update (binding);
 }