Comment 5 for bug 1819212

Reviewed: https://review.openstack.org/642847
Committed: https://git.openstack.org/cgit/openstack/os-net-config/commit/?id=21dfd95bbe8268ddc30cefc5ac5ea92a573d5155
Submitter: Zuul
Branch: stable/rocky

commit 21dfd95bbe8268ddc30cefc5ac5ea92a573d5155
Author: Dan Sneddon <email address hidden>
Date: Fri Mar 8 15:46:34 2019 -0800

    Fix os-net-config interface restarts when applying routes

    There is a bug in the os-net-config code that applies updates to
    existing routes. Instead of deleting routes that no longer exist
    in the config and adding routes on the fly that do, the process
    always fails so the interface gets restarted.

    This change fixes the external call to "/sbin/ip", but also
    fixes a bug where the name of the file containing the stored
    routes was being passed incorrectly. This caused os-net-config
    to always think there were no routes present, and to apply the
    new route without deleting the old route. This can lead to an
    error if the routes conflict.

    Change-Id: I4315e9812c641a667a1d5c6529cdba5d2f5bf640
    Closes-bug: 1819212
    (cherry picked from commit e912b02c3bec61ec3af610820601cc24b5dc1cba)