Move cfg to keystone.openstack.common

Just code movement here, no changes.

This is so we can use openstack-common's update script to keep it in
sync. See:

  http://wiki.openstack.org/CommonLibrary#Incubation

Change-Id: Ieb8ce50071a85987152b995fa6773433b7671c48

keystone/config.py

@@ -18,8 +18,8 @@ import gettext
 import sys
 import os
 
-from keystone.common import cfg
 from keystone.common import logging
+from keystone.openstack.common import cfg
 
 
 gettext.install('keystone', unicode=1)