Comment 1 for bug 1556182

Reviewed: https://review.openstack.org/336805
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=a984f9554cdcbe93c840a1d8f5c04302e9331e79
Submitter: Jenkins
Branch: master

commit a984f9554cdcbe93c840a1d8f5c04302e9331e79
Author: Ihar Hrachyshka <email address hidden>
Date: Sat Jul 2 17:30:21 2016 +0200

    Calculate MTU on every network fetch instead of on create

    Today, existing networks may not reflect MTU configured for
    neutron-server, if they were created when neutron-server was using
    different MTU setup for its infrastructure, or when it was using bad
    default values for network MTUs (specifically, before Mitaka, all networks
    were getting MTU = 0 by default, disabling both advertisement and data
    path MTU size enforcement).

    This patch stops persisting MTU in the database on network create and
    instead calculate it on every network resource fetch.

    DocImpact Now changes to MTU configuration options immediately affect
              existing network MTUs, not just new networks.

    UpgradeImpact Existing networks with invalid MTU persisted in database
                  may change their MTU values to reflect configuration.

    Change-Id: Iee4f5037bf10b73ba98464143b183aacb59c22f2
    Closes-Bug: #1556182