Comment 2 for bug 1554173

Reviewed: https://review.openstack.org/289521
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=edff6fbf5d80dba05ab57b557ee25f44098bdf13
Submitter: Jenkins
Branch: master

commit edff6fbf5d80dba05ab57b557ee25f44098bdf13
Author: Ryan McNair <email address hidden>
Date: Mon Mar 7 18:42:22 2016 +0000

    Don't disallow quota deletion if allocated < 0

    Due to the race condition http://bugs.launchpad.net/cinder/+bug/1552944,
    it's possible that a volume delete on a project at the same time as a
    change to/from a -1 limit on the project could double count the change
    in allocated value. This has the possibility to set allocated < 0, and
    in order to handle this situation as gracefully as possible, we should
    not disallow quota deletion in the case that allocated < 0.

    Change-Id: Ic35ff9671024aa1cecc04b205d1b7cba56bbea61
    Closes-Bug: #1554173