The charm provides its own handler for appearance of `amqp.connected`
flag.
Add workaround for intermittent test failures to functional test.
Depends-On: https://github.com/openstack-charmers/zaza/pull/89
Closes-Bug: #1784083
Change-Id: Iefa1c4bf2a447b8c6126a417887512cc10a1b78e