Add a note for how to get prior release kolla doc
Add a note for how to get prior release kolla doc

Change-Id: Iff8185ebd39f633512a20a07889bd01b6ee4e037

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