Comment 4 for bug 1417464

Reviewed: https://review.openstack.org/172038
Committed: https://git.openstack.org/cgit/openstack/oslo.messaging/commit/?id=671c60d3a5c21169978805ca4ed616941a3aeabf
Submitter: Jenkins
Branch: stable/kilo

commit 671c60d3a5c21169978805ca4ed616941a3aeabf
Author: zhangjl <email address hidden>
Date: Tue Feb 3 18:56:47 2015 +0800

    Fix the bug redis do not delete the expired keys

    When using redis as zmq backend,
    the keys in redis maybe like follows:

     "service"
     "service.host1"
     "service.host1.host1"
     "service.host2"
     "service.host2.host2"
     "service.host3"
     "service.host3.host3"

    If we stopped the service on host1, the key named
    service.host1 and service.host1.host1 shoule be
    delete. As the result, the topicexchange message
    would not sent to host1. But the fact is
    service.host1 still exsit, and topicexchange
    message may still sent to host1.

    To resolve this problem , change the comparison of
    ttl function from -1 to -2 according to
    http://redis.io/commands/ttl

    Change-Id: I5c0af97019fffed6e949eb58d7d60c85f5b08ea1
    Closes-Bug:#1417464
    (cherry picked from commit 1958f6e549d3769202960f5af93982afea74cd80)