Comment 2 for bug 1264360

Reviewed: https://review.openstack.org/64193
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=8328fc46d783f4ec9286eededafa91afae89cba0
Submitter: Jenkins
Branch: master

commit 8328fc46d783f4ec9286eededafa91afae89cba0
Author: Alan Meadows <email address hidden>
Date: Thu Dec 26 11:12:37 2013 -0800

    Bugfix missing foreign key removal for mysql

    Downgrading the cinder schema fails when running 018_add_qos_specs.py
    under MySQL. The upgrade path of this schema patch adds the foreign
    key volume_types_ibfk_1 on table volume_types, and the downgrade does
    not correspondingly remove it before attempting to drop the
    qos_specs_id column. This update removes the foreign key when
    the engine is mysql prior to dropping the column.

    Change-Id: Ibd3b35ad3b0bd41ad04ab7aeeb28c3ba7e5d255d
    Closes-Bug: #1264360