Comment 2 for bug 1902002

Reviewed: https://review.opendev.org/760325
Committed: https://git.openstack.org/cgit/openstack/devstack/commit/?id=47f76acbbac350ea18df6a9463876d38c3a13539
Submitter: Zuul
Branch: master

commit 47f76acbbac350ea18df6a9463876d38c3a13539
Author: Jens Harbott <email address hidden>
Date: Thu Oct 29 10:42:38 2020 +0000

    Determine default IPv4 route device only when needed

    Sometimes instances don't have an IPv4 default route, so only check for
    it when we actually need it. In a followup patch we could extend the
    code to check for an IPv6 default route instead or in addition.

    Related-Bug: 1902002
    Change-Id: Ie6cd241721f6b1f8e030960921a696939b2dab10