[libchamplain] Set the polygons list to NULL after the free in champlain_view_dispose().

[Pierre-Luc Beaudoin <plbeaudoin src gnome org>]

commit 6e3058df141390771fb6ebcc2cc8284acb36202b
Author: Emmanuel Rodriguez <emmanuel rodriguez gmail com>
Date:   Wed Jun 17 21:00:55 2009 +0200

    Set the polygons list to NULL after the free in champlain_view_dispose().
    
    If the list isn't set to NULL then an application would have wrong memory
    access in the case where dispose is called twice for the same object. This
    happens on the demo launcher-gtk.

 champlain/champlain-view.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c
index 28f56e3..61329b3 100644
--- a/champlain/champlain-view.c
+++ b/champlain/champlain-view.c
@@ -719,6 +719,7 @@ champlain_view_dispose (GObject *object)
       polygons = polygons->next;
     }
   g_list_free (priv->polygons);
+  priv->polygons = NULL;
 
   if (priv->goto_context != NULL)
     champlain_view_stop_go_to (view);