Comment 6 for bug 1840443

Reviewed: https://review.opendev.org/677054
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=3a2842bdd8d8d59e445393c7c7e7a9793357df08
Submitter: Zuul
Branch: stable/stein

commit 3a2842bdd8d8d59e445393c7c7e7a9793357df08
Author: Slawek Kaplonski <email address hidden>
Date: Fri Aug 16 13:44:09 2019 +0000

    Initialize phys bridges before setup_rpc

    Neutron-ovs-agent configures physical bridges that they works
    in fail_mode=secure. This means that only packets which match some
    OpenFlow rule in the bridge can be processed.
    This may cause problem on hosts with only one physical NIC
    where same bridge is used to provide control plane connectivity
    like connection to rabbitmq and data plane connectivity for VM.
    After e.g. host reboot bridge will still be in fail_mode=secure
    but there will be no any OpenFlow rule on it thus there will be
    no communication to rabbitmq.

    With current order of actions in __init__ method of OVSNeutronAgent
    class it first tries to establish connection to rabbitmq and later
    configure physical bridges with some initial OpenFlow rules.
    And in case described above it will fail as there is no connectivity
    to rabbitmq through physical bridge.

    So this patch changes order of actions in __init__ method that it first
    setup physical bridges and than configure rpc connection.

    Change-Id: I41c02b0164537c5b1c766feab8117cc88487bc77
    Closes-Bug: #1840443
    (cherry picked from commit d41bd58f31e259fe408c8c059b31299fdfe81127)