[libchamplain] Fix crash on shutdown

[Jiří Techet <jiritechet src gnome org>]

commit 0a5c11e2223c42f01649b55987d2c57a00569a62
Author: JiÅ?í Techet <techet gmail com>
Date:   Sun Feb 13 02:31:32 2011 +0100

    Fix crash on shutdown

 champlain/champlain-view.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/champlain/champlain-view.c b/champlain/champlain-view.c
index 85e9b1d..46d2cce 100644
--- a/champlain/champlain-view.c
+++ b/champlain/champlain-view.c
@@ -554,7 +554,10 @@ champlain_view_dispose (GObject *object)
     champlain_view_stop_go_to (view);
 
   if (priv->update_viewport_timer != NULL)
-    g_timer_destroy (priv->update_viewport_timer);
+    {
+      g_timer_destroy (priv->update_viewport_timer);
+      priv->update_viewport_timer = NULL;
+    }
 
   G_OBJECT_CLASS (champlain_view_parent_class)->dispose (object);
 }