Comment 4 for bug 1605423

Reviewed: https://review.openstack.org/345707
Committed: https://git.openstack.org/cgit/openstack-dev/devstack/commit/?id=6a42a85b561c35157b14f63ab02536e18e5bb0d9
Submitter: Jenkins
Branch: master

commit 6a42a85b561c35157b14f63ab02536e18e5bb0d9
Author: Kevin Benton <email address hidden>
Date: Thu Jul 21 11:11:54 2016 -0700

    Fixes for linux bridge and Q_USE_PROVIDER_NET

    ===Set bridge_mappings for linux bridge===
    The external network physnet needs a bridge_mapping to the public
    bridge when the L2 agent is responsible for wiring.

    ===Add PUBLIC_PHYSICAL_NETWORK to flat_networks===
    This network must be present in the ML2 flat_networks config if
    flat_networks is specified.

    ===Set ext_gw_interface to PUBLIC_BRIDGE in provider net case===
    ext_gw_interface must be a bridge in a bridge_mapping when
    Q_USE_PROVIDERNET_FOR_PUBLIC is used.

    Closes-Bug: #1605423
    Change-Id: I95d63f8dfd21499c599d425678bf5327b599efcc