Fix for gnome keyring import problems

(patch by Christoph Mathys)

mercurial_keyring.py

@@ -56,6 +56,7 b' if "gobject._gobject" not in ignore:'
     ignore.append("json")
     ignore.append("abc")
     ignore.append("io")
+    ignore.append("keyring")
 
 import keyring
 from urlparse import urlparse