Comment 4 for bug 1627691

Reviewed: https://review.openstack.org/376010
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=98de72e9f32090a93c9c1b6f45cc0f2385c27792
Submitter: Jenkins
Branch: master

commit 98de72e9f32090a93c9c1b6f45cc0f2385c27792
Author: Kevin Benton <email address hidden>
Date: Sat Sep 24 01:53:38 2016 -0700

    Don't try to delete non-existent namespace

    The namespace in the DHCP agent may already have been
    deleted by a previous event when _destroy_namespace_and_port
    is called (e.g. all subnets deleted from network and then network
    is deleted). To avoid log errors every time this happens, check
    for the existence of the namespace before trying to delete it.

    Closes-Bug: #1627691
    Change-Id: I204ba7a0de056f13af505541d67f0acdd70fd54d