Explain how to use kolla-ansible pull
Explain how to use kolla-ansible pull

During multi-node, it is possible for master target node images to
be older then the Ansible master playboks if the repository is
updated.  Add documentation to explain this situation.

Change-Id: I2ccf57004147873e89f23fbb996d01f550e90c3f

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