Adjust swift_rings.py to work on specified regions
Adjust swift_rings.py to work on specified regions

This patch allows the swift_ring.py to only adjust/add/remove nodes from
a specified region, leaving the other regions that are already in the
ring unmodified.

This will allow multi-region swift to be managed by separate locations
each managing their own region's nodes and leaving other regions to
handle their own nodes.

The default is to manage all regions, so not specifying a region will
work the same as it does now and the script's functionality remains
unchanged.

Change-Id: I1cf73be20f27c437450c0181bb247c86e0f46bc6
Partially-Implements: blueprint multi-region-swift
(cherry picked from commit c927f4205e1da08467d4873d388093a4282f92a6)

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