Comment 4 for bug 1609304

Reviewed: https://review.openstack.org/350534
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=9e9b3ec7ea29a636f8847dc1022c37f0e442fc26
Submitter: Jenkins
Branch: master

commit 9e9b3ec7ea29a636f8847dc1022c37f0e442fc26
Author: Michał Dulko <email address hidden>
Date: Tue Aug 2 18:25:45 2016 +0200

    Pin RPC server's serializer to min obj version

    We're passing object version pin on CinderObjectSerializer
    initialization in RPC clients (rpcapis), but not in RPC servers
    (managers). This means that objects returned from RPC calls aren't
    backported and older service can get a response with an object version
    it doesn't understand. As on RPC server side we don't know who called
    us, we need to consider minimum object version among all the binaries,
    not only the one we're running.

    This commit implements that behavior.

    Closes-Bug: 1609304
    Change-Id: Ibc708eb6ca6d792bec0f38abb4e1b5f58488a414