Comment 3 for bug 1509959

Reviewed: https://review.openstack.org/239264
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=6ac43c119bff9da93f438d10033b209819a32230
Submitter: Jenkins
Branch: master

commit 6ac43c119bff9da93f438d10033b209819a32230
Author: Eugene Nikanorov <email address hidden>
Date: Sun Oct 25 15:47:38 2015 +0400

    Cleanup dhcp namespace upon dhcp setup.

    In some cases when more than 1 DHCP agents were assigned
    to a network and then they became dead, their DHCP ports
    become reserved. Later, when those agents revive or start
    again, they acquire reserved ports, but it's not guaranteed
    that they get exactly same ports. In such case DHCP agent
    may create interface in the namespaces despite that another
    interface already exist. In such case there will be two
    hosts with dhcp namespaces each containing duplicate ports,
    e.g. one port will be present on two hosts. This breaks
    DHCP.

    Closes-Bug: #1509959
    Change-Id: I34eb1ad5c44dd3528c9910462e26536186e7a4fb