Add md5sum check for swift rings after ring-sync
Add md5sum check for swift rings after ring-sync

Moving towards multi-region swift there is a chance that 2 regions will
attempt to update the ring at the same time. Whilst measures are in
place to ensure a region only updates its own region entries in the
ring it would still be possible, if the 2 runs happened simultaneously,
that some ring inconsistencies could happen. For example, if a region A
updates at the same time as region B but the sync order is different
some nodes could have region A's "updated" ring and some with region
B's "updated" ring.

To ensure this hasn't happened (without our knowledge) this patch adds
another md5sum check which will report if the rings are inconsistent
across the nodes.

Change-Id: Id88dfebcaa0553437953f92235bf63363f750797
Partially-Implements: blueprint multi-region-swift
(cherry picked from commit e1603af4f5f9877950dca08fb3e7e1bccb342efb)

VaneCloud/openstack-ansible,VaneCloud/openstack-ansible,yanyao/openstack-deployment,yanyao/openstack-deployment,yanyao/openstack-deployment,VaneCloud/openstack-ansible,yanyao/openstack-deployment