Comment 13 for bug 1830081

Reviewed: https://review.opendev.org/711251
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=3e935325a88bf7a0206ec07bc67383e8be846f15
Submitter: Zuul
Branch: stable/train

commit 3e935325a88bf7a0206ec07bc67383e8be846f15
Author: Stephen Finucane <email address hidden>
Date: Wed Jun 5 16:39:45 2019 +0100

    Unplug VIFs as part of cleanup of networks

    If an instance fails to build, which is possible for a variety of
    reasons, we may end up in a situation where we have remnants of a
    plugged VIF (typically files) left on the host. This is because we
    cleanup from the neutron perspective but don't attempt to unplug the
    VIF, a call which may have many side-effects depending on the VIF
    driver. Resolve this by always attempting to unplug VIFs as part of the
    network cleanup.

    A now invalid note is also removed and a unit test corrected.

    Conflicts:
     nova/tests/unit/compute/test_compute_mgr.py

    NOTE(stephenfin): Conflicts are due to the absence of change
    Ifa9c5c468400261a5e1f66b72c575845173a4f8f ("nova-net: Remove final
    references to nova-network") which we don't want to backport here. In
    addition, we need to modify a mock to reflect the absence of change
    I329f0fd589a4b2e0426485f09f6782f94275cc07 ("nova-net: Remove layer of
    indirection in 'nova.network'").

    Closes-Bug: #1831771
    Related-Bug: #1830081
    Signed-off-by: Stephen Finucane <email address hidden>
    Change-Id: Ibdbde4ed460a99b0cbe0d6b76e0e5b3c0650f9d9
    (cherry picked from commit b3e14931d6aac6ee5776ce1e6974c75a5a6b1823)