[d-feet] fix crash on empty selection

[John Palmieri <johnp src gnome org>]

commit c917ff09e352300b41e34bb39ffe420ee24ada4a
Author: Robert Ancell <robert ancell canonical com>
Date:   Tue Nov 15 08:59:27 2011 -0500

    fix crash on empty selection

 dfeet/_ui/busnameinfobox.py |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)
---
diff --git a/dfeet/_ui/busnameinfobox.py b/dfeet/_ui/busnameinfobox.py
index 8041a43..6fbecf6 100644
--- a/dfeet/_ui/busnameinfobox.py
+++ b/dfeet/_ui/busnameinfobox.py
@@ -95,9 +95,9 @@ class BusNameInfoBox(gtk.VBox):
 
     def cursor_changed_handler(self, treeview):
         node = self.get_selected_node()
-        node.on_selected(self.busname)
-
-        self.emit('selected', node)
+        if node:
+            node.on_selected(self.busname)
+            self.emit('selected', node)
 
     def get_selected_node(self):
         selection = self.introspect_tree_view.get_selection()