Updated openstack/openstack
Project: openstack/heat  9f2378fc02871af899e4f959e21416313f8ef1be
null
Implement engine listener service for multi-engine support

The engine listener service provides a way for engines to confirm that
other engines are still alive.  For example, during acquisition of a
stack lock, if an existing stack lock is found the engine will attempt
to communicate with the engine who owns that lock.  If the engine
responds affirmatively, the lock will be considered active.

Blueprint multiple-engines

Change-Id: I6d8f1305953212408f19688a1e0af81c44e5e5b4