Comment 6 for bug 1612875

Reviewed: https://review.openstack.org/374975
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=2ce193e16d7ca5b93671d7f0d2e3b35761f5d386
Submitter: Jenkins
Branch: master

commit 2ce193e16d7ca5b93671d7f0d2e3b35761f5d386
Author: Matt Riedemann <email address hidden>
Date: Thu Sep 22 12:41:46 2016 -0400

    libvirt: ignore conflict when defining network filters

    We have a latent race in the libvirt firewall code when setting
    up static filters which is now an error with libvirt>=1.2.7,
    which is why we started seeing this in CI failures starting in
    newton which run on xenial nodes that have libvirt 1.3.1 (but
    didn't see it on trusty nodes with libvirt 1.2.2).

    Libvirt commit 46a811db0731cedaea0153fc223faa6096cee5b5 checks
    for an existing filter with the same name but a different uuid
    when defining network filters and raises an error if found. That
    was added in the 1.2.7 release.

    This change simply handles the error and ignores it so we don't
    fail to boot the instance.

    Unfortunately we don't have a specific error code from libvirt
    when this happens so the best we can do is compare the error
    message from the libvirt error which is only going to work for
    English locales because the error message from libvirt is
    translated.

    Change-Id: I161be26d605351f168e351d3ed3d308234346f6f
    Closes-Bug: #1612875