Comment 6 for bug 1797084

Reviewed: https://review.opendev.org/c/openstack/neutron/+/795624
Committed: https://opendev.org/openstack/neutron/commit/8b1ddc5083e7033702eee9051860ced4d2b6a721
Submitter: "Zuul (22348)"
Branch: stable/rocky

commit 8b1ddc5083e7033702eee9051860ced4d2b6a721
Author: Daniel Alvarez <email address hidden>
Date: Wed Oct 10 10:25:17 2018 +0200

    Exclude fallback tunnel devices from netns cleanup

    When a namespace gets created, if the fb_tunnels_only_for_init_net
    sysctl configuration is set to 0, the fallback tunnels will be
    automatically created if the corresponding tunnel is present
    in the initial network namespace. Source [0].

    This is being observed in some systems where namespaces are not
    getting cleaned up due to the presence of such devices as
    ip_lib.namespace_is_empty() is returning False.

    This patch is adding such devices as per the kernel documentation
    to the list of excluded devices by default.

    [0] https://www.kernel.org/doc/Documentation/sysctl/net.txt

    Closes-Bug: #1797084
    Change-Id: I94415a0da5367e2d98d792a5eb4ba3919b838326
    Signed-off-by: Daniel Alvarez <email address hidden>
    (cherry picked from commit 8e60531d11401c2c509a1255b49f89bc2bf81a74)