Comment 4 for bug 1235486

Reviewed: https://review.openstack.org/49644
Committed: http://github.com/openstack/neutron/commit/ed78b563e13f1ed9189d7c4b9cd4317f2a50e734
Submitter: Jenkins
Branch: master

commit ed78b563e13f1ed9189d7c4b9cd4317f2a50e734
Author: Bob Kukura <email address hidden>
Date: Thu Oct 3 12:25:24 2013 -0400

    Fix auto-deletion of ports when deleting subnets in ML2

    When a subnet is deleted, certain ports referencing it are
    auto-deleted. The implementation of NeutronDBPluginV2.delete_subnet()
    does this at the DB level, so ML2's mechanism drivers were not being
    called.

    Ml2Plugin.delete_subnet() is changed to not use the base class's
    method, and to auto-delete ports by calling its own delete_port()
    method outside of the transaction. A loop avoids race conditions with
    ports being asynchronously added to the subnet.

    The logic in Ml2Plugin.delete_network() is also fixed to properly
    handle auto-deleting ports and subnets, and debug logging is added to
    the various delete methods.

    Closes-Bug: 1234195
    Partial-Bug: 1235486
    Change-Id: I6d74f89d39ea8afe6915f1d2f9afdf66c0076f5a