Updated openstack/openstack
Project: openstack/neutron  5168a4b5137d28cff10e8f6aa1b3deb0a12d2f83

Make readme reference git.openstack.org not github

Point to our offical mirror instead of github.

Change-Id: I43c3d5ce4f92f35ed4fe5bddce5a5d19016ab988