Refined documentation regarding registry
Refined documentation regarding registry

The documentation had old information about running
docker registry version 1.  Documentation improvement
uses exclusively Docker register version 2.

TrivialFix

Change-Id: I320341c1a646eeeec35fb928a970f4d7e8a13bb9

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