Comment 7 for bug 1843870

Reviewed: https://review.opendev.org/731541
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=3e7abdf7acbb53ce7262c26e9078dbd453eb6cb0
Submitter: Zuul
Branch: stable/stein

commit 3e7abdf7acbb53ce7262c26e9078dbd453eb6cb0
Author: Lucian Petrut <email address hidden>
Date: Thu Sep 12 17:34:04 2019 +0300

    ovsdb monitor: handle modified ports

    This patch ensures that the ovsdb monitor propagates the events
    received for modified ports.

    We'll use a new list for the modified ports, which the neutron ovs
    agent can handle.

    In particular, this will cover the situation in which the ofport
    changes. When using recent OVS Windows versions, VM ofports change
    to -1 (invalid) when the VMs are shut down, receiving a valid
    ofport when the VMs are powered back on (different than the initial
    one). With this patch applied, "modify" events will be propagated
    to the ovs agent, which will then update the OpenFlow rules.
    The old rules are cleaned up by "update_stale_ofport_rules"
    once the invalid ofport is detected.

    Closes-Bug: #1843870
    Co-authored-by: Alin Serdean <email address hidden>

    Conflicts:
          neutron/plugins/ml2/drivers/openvswitch/agent/ovs_neutron_agent.py

    Change-Id: I0c3a570cbb3fbb03b4224744b32e034e9e255f8e
    (cherry picked from commit 451c21571f40ca83eb3189e5c924b03c0561f853)
    (cherry picked from commit 4991325054689a6ffde3afde725b43bbe1f8b584)