No need to initialize gtk threads, glib is enough.

Fix lockups in the browser.

shell/sugar-activity-factory

@@ -4,11 +4,12 @@ import logging
 
 import pygtk
 pygtk.require('2.0')
+import gobject
 import gtk
 import dbus.glib
 
 # Work around for dbus mutex locking issue
-gtk.gdk.threads_init()
+gobject.threads_init()
 dbus.glib.threads_init()
 
 from sugar.activity import ActivityFactory