Add basic tests for 0mq matchmakers

Basic unit tests for in-memory (localhost), ring and Redis based
matchmakers.

Redis tests are opportunitic based on a redis-server being installed
and running.

Test are currently skipped under py3 due to direct dependency on
eventlet.

Co-Authored-By: Kapil Thangavelu <kapil.thangavelu@canonical.com>
Change-Id: I59c4d095033370ab94f645af0d50e2502530f816
Partial-bug: #1302941
Merge "Add basic tests for 0mq matchmakers"