Comment 9 for bug 1813714

Reviewed: https://review.openstack.org/645408
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=62fe7852bbd70a24174853997096c52ee015e269
Submitter: Zuul
Branch: stable/pike

commit 62fe7852bbd70a24174853997096c52ee015e269
Author: LIU Yulong <email address hidden>
Date: Mon Mar 4 21:17:20 2019 +0800

    More accurate agent restart state transfer

    Ovs-agent can be very time-consuming in handling a large number
    of ports. At this point, the ovs-agent status report may have
    exceeded the set timeout value. Some flows updating operations
    will not be triggerred. This results in flows loss during agent
    restart, especially for hosts to hosts of vxlan tunnel flow.

    This fix will let the ovs-agent explicitly, in the first rpc loop,
    indicate that the status is restarted. Then l2pop will be required
    to update fdb entries.

    Conflicts:
     neutron/plugins/ml2/rpc.py

    Conflicts:
     neutron/plugins/ml2/drivers/l2pop/mech_driver.py

    Closes-Bug: #1813703
    Closes-Bug: #1813714
    Closes-Bug: #1813715
    Closes-Bug: #1794991
    Closes-Bug: #1799178

    Change-Id: I8edc2deb509216add1fb21e1893f1c17dda80961
    (cherry picked from commit a5244d6d44d2b66de27dc77efa7830fa657260be)
    (cherry picked from commit cc49ab550179bdc76d79f48be67886681cb43d4e)
    (cherry picked from commit 5ffca4966877454c605442e9e429aa83ea7d7348)