Comment 9 for bug 1494114

Reviewed: https://review.openstack.org/222873
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=dafa61bd46b7eacbc708d17a3fa492de971d6dd2
Submitter: Jenkins
Branch: master

commit dafa61bd46b7eacbc708d17a3fa492de971d6dd2
Author: armando-migliaccio <email address hidden>
Date: Sat Sep 12 12:07:35 2015 -0700

    Fix BadRequest error on add_router_interface for DVR

    This operation for DVR is made of multiple steps, some of
    which are not within the same DB transaction. For this
    reason, if a failure occurs, the rollback will be partial.

    This inconsistent state leads the retry logic to fail with
    BadRequest, because the router is believed to be already
    connected to the subnet.

    To fix this condition, it is necessary to delete the port
    should the DB deadlock occur.

    Closes-bug: #1494114

    Change-Id: Ia2a73d6f9d1e4746e761ad072d954e64267a3ad1