[pygobject] Fix usage of TreeIter api that is now an override.

[Paolo Borelli <pborelli src gnome org>]

commit 167a01c46b3fa0b3c8339502c875d32bd2bca974
Author: Paolo Borelli <pborelli gnome org>
Date:   Wed Dec 8 17:37:00 2010 +0100

    Fix usage of TreeIter api that is now an override.

 demos/gtk-demo/gtk-demo.py |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/demos/gtk-demo/gtk-demo.py b/demos/gtk-demo/gtk-demo.py
index 41edc32..da0cb88 100755
--- a/demos/gtk-demo/gtk-demo.py
+++ b/demos/gtk-demo/gtk-demo.py
@@ -244,10 +244,10 @@ class GtkDemoApp(object):
                                     text = 0,
                                     style = 2)
 
+        first_iter = tree_store.get_iter_first()
+        if first_iter is not None:
+            selection.select_iter(first_iter)
 
-
-        (success, first_iter) = tree_store.get_iter_first()
-        selection.select_iter(first_iter)
         selection.connect('changed', self.selection_cb, tree_store)
         tree_view.connect('row_activated', self.row_activated_cb, tree_store)