Comment 10 for bug 1713875

Reviewed: https://review.openstack.org/604612
Committed: https://git.openstack.org/cgit/openstack/designate/commit/?id=7c2a3be3e42cc72b6b03c9b6cb67393d423e5e21
Submitter: Zuul
Branch: stable/pike

commit 7c2a3be3e42cc72b6b03c9b6cb67393d423e5e21
Author: Arjun Baindur <email address hidden>
Date: Tue Jul 31 14:36:32 2018 -0700

    Make update_status use synchronized_zone

    There is a race condition when adding a new recordset to a zone
    and when central is processing the update_status from a previous
    recordset/zone operation. In the subsequent recordset operation,
    central fails to update the zone's action/status in DB to UPDATE/PENDING.
    It remains as NONE/ACTIVE, and worker error's out.

    Each operation retrieves a different copy in memory of the Zone object
    (when it calls self.storage.get_zone). As a result this does not update
    the obj_changes field for the zone object for the latter operation.
    Therefore the DB update doesn't update any values.

    update_status should be synchronized as it updates zone DB

    Change-Id: Ib4e0bc567ba8eb54c61c3921d165521bf2f12206
    Closes-Bug: #1713875
    (cherry picked from commit 12cd654b143e215dbe01cc2688a7d6e6cf3ce62f)