Comment 21 for bug 1744160

Reviewed: https://review.openstack.org/536182
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=d24963f7e84b519864ece4fce99f9b0da0204da4
Submitter: Zuul
Branch: master

commit d24963f7e84b519864ece4fce99f9b0da0204da4
Author: junboli <email address hidden>
Date: Mon Jan 22 09:28:42 2018 +0800

    Handle TZ change in iso8601 >=0.1.12

    The iso8601 lib introduced a change such that if running on python
    3.2 or later it internally uses the python timezone information
    instead of its own implementation. This does not change direct
    date handling, but when converting this value there is a slight
    difference where now python 2.x will show UTC times as "UTC", but
    on python 3 they will end up with "UTC+00:00".

    The to_primitive call for DateTime fields was doing an exact match
    on "UTC" to determine whether to include "Z" in the resulting string.
    This updates that handling to recognize either of the new values.

    Change-Id: Idfefd41e45727a375a5ea296a3348716c43f17b5
    Closes-bug: #1744160