Comment 4 for bug 1514459

Reviewed: https://review.openstack.org/249593
Committed: https://git.openstack.org/cgit/openstack/mistral/commit/?id=73d783eb90676a42a59495246d316421417ea2e1
Submitter: Jenkins
Branch: stable/liberty

commit 73d783eb90676a42a59495246d316421417ea2e1
Author: Lingxian Kong <email address hidden>
Date: Mon Nov 9 22:47:29 2015 +0800

    Removing wait() when initializing notification listener

    According to [1],the correct usage is to call stop() before wait(), so in
    mistral case, we should never call stop() and wait() in initialization of
    engine and executor service.

    [1]:
    http://docs.openstack.org/developer/oslo.messaging/notification_listener.html

    Change-Id: Ic6a802bff35a6a6fdfadf38474782efd12fd34d8
    Closes-Bug: #1514459
    (cherry picked from commit ec28a305d91139ef5d307fa56ad289a635e37a90)