Sync matchmaker_ring.py from oslo-incubator

Cinder does not currently include the matchmaker driver, which is the
preferred configuration with ZeroMQ.

Change-Id: I8514f1780e6492f9d37134d282a5196709347bd8
Partial-Bug: #1185690
Merge "Sync matchmaker_ring.py from oslo-incubator"
Merge remote-tracking branch 'origin/master' into jiocloud_devmaster