Add upgrade check for removed "external_network_bridge" config option

[Slawek Kaplonski]

In patch https://review.openstack.org/#/c/567369/ we finally removed config option "external_network_bridge" from neutron.
Now it could be nice to have upgrade check which will check if this config option is used by any of L3 agents and if it is, than warn operator that migration to new connect way (via br-int) will be needed.

[Slawek Kaplonski (slaweq)]

Patch proposed: https://review.openstack.org/#/c/643486/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/643486
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=6ee786ab95c2797822698c16e688fd00a7a944a1
Submitter: Zuul
Branch: master

commit 6ee786ab95c2797822698c16e688fd00a7a944a1
Author: Slawek Kaplonski <email address hidden>
Date: Fri Mar 15 00:17:10 2019 +0100

    Add check for external_network_bridge in neutron-status

    In commit [1] old config options "external_network_bridge"
    was removed.
    This patch adds upgrade check which will warn operator
    if any of their L3 agents is still using this config option.

    [1] https://review.openstack.org/#/c/567369/

    Closes-Bug: #1820763

    Change-Id: I92b1e30e806dfd20d99716d31c518845fd296a3d

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 14.0.0.0rc1 release candidate.