Comment 6 for bug 1562083

Reviewed: https://review.openstack.org/302462
Committed: https://git.openstack.org/cgit/openstack/swift/commit/?id=3083f5700c0c12c8caef638b013730805ac06ff6
Submitter: Jenkins
Branch: stable/mitaka

commit 3083f5700c0c12c8caef638b013730805ac06ff6
Author: Tim Burke <email address hidden>
Date: Wed Mar 30 14:19:00 2016 -0700

    Fix upgrade bug in versioned_writes

    Previously, versioned_writes assumed that all container servers would
    always have the latest Swift code, allowing them to return reversed
    listings. This could cause the wrong version of a file to be restored
    during rolling upgrades.

    Now, versioned_writes will check that the listing returned is actually
    reversed. If it isn't, we will revert to getting the full (in-order)
    listing of versions and reversing it on the proxy.

    Change-Id: Ib53574ff71961592426cb386ef00a75eb5824def
    Closes-Bug: 1562083
    (cherry picked from commit ebf0b220127b14bec7c05f1bc0286728f27f39d1)