Set namespace to point to local registry
Set namespace to point to local registry

`kolla-build --push` will push to local registry.

Partially-Implements: blueprint vagrant-improvements
Change-Id: Id841ad9845db6270b6051f7e0a1f93bccbf686fe

limamauricio/mykolla,toby82/kolla,rajalokan/kolla,negronjl/kolla,GalenMa/kolla,rajalokan/kolla,limamauricio/mykolla,rajalokan/kolla,tonyli71/kolla,tonyli71/kolla,GalenMa/kolla,negronjl/kolla,rahulunair/kolla,stackforge/kolla,negronjl/kolla,nihilifer/kolla,mrangana/kolla,openstack/kolla,limamauricio/mykolla,rahulunair/kolla,dardelean/kolla-ansible,dardelean/kolla-ansible,dardelean/kolla-ansible,coolsvap/kolla,toby82/kolla,intel-onp/kolla,mandre/kolla,mandre/kolla,mandre/kolla,fdumpling/kolla,toby82/kolla,fdumpling/kolla,openstack/kolla,stackforge/kolla,coolsvap/kolla,fdumpling/kolla,coolsvap/kolla,mrangana/kolla,nihilifer/kolla,intel-onp/kolla,stackforge/kolla