Comment 20 for bug 1840895

Reviewed: https://review.opendev.org/682557
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=7156ebfc2853ceeeeb94b7a4f9046eeb256051c1
Submitter: Zuul
Branch: stable/stein

commit 7156ebfc2853ceeeeb94b7a4f9046eeb256051c1
Author: Slawek Kaplonski <email address hidden>
Date: Fri Aug 30 22:32:19 2019 +0200

    Fix creation of vlan network with segmentation_id set to 0

    In case when vlan network was created with segmentation_id=0 and without
    physical_network given, it was passing validation of provider segment
    and first available segmentation_id was choosen for network.
    Problem was that in such case all available segmentation ids where
    allocated and no other vlan network could be created later.

    This patch fixes validation of segmentation_id when it is set to value 0.

    Change-Id: Ic768deb84d544db832367f9a4b84a92729eee620
    Closes-bug: #1840895
    (cherry picked from commit f01f3ae5dd0dd7dd9aa513a1b50e04e20a08b97b)