Cleanup WSGI config for keystone on stop

Ensure that the VHOST and the scripts used to enable keystone under
mod_wsgi are properly cleaned up.

Change-Id: I76a748b0fd5f1a5182d10e425202857c5621e25a
diff --git a/lib/keystone b/lib/keystone
index b31cc57..ba3a519 100644
--- a/lib/keystone
+++ b/lib/keystone
@@ -450,6 +450,8 @@
 function stop_keystone {
     # Kill the Keystone screen window
     screen_stop key
+    # Cleanup the WSGI files and VHOST
+    _cleanup_keystone_apache_wsgi
 }