database downgrade from 5_0_1 fails for nailgun

[Dima Shulyak]

on clear nailgun database perform:

./manage.py migrate upgrade head

./manage.py migrate downgrade base or /.manage.py migrate downgrade 1a1504d469f8

it will fail with:

sqlalchemy.exc.ProgrammingError: (ProgrammingError) constraint "pending_release_id" of relation "clusters" does not exist
 'ALTER TABLE clusters DROP CONSTRAINT pending_release_id' {}

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/99311

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/99311
Committed: https://git.openstack.org/cgit/stackforge/fuel-web/commit/?id=b796d6f827da989328f695bcc64cf628baf2d1f3
Submitter: Jenkins
Branch: master

commit b796d6f827da989328f695bcc64cf628baf2d1f3
Author: Dima Shulyak <email address hidden>
Date: Wed Jun 11 12:41:53 2014 +0300

    Fix migration scripts in nailgun

    - 5_0_1 droping pending_relese_id by wrong name
    - 5_0 enums is not dropped by default

    Change-Id: I4abf67f6f547ae5b15c773b80b3d09e4914d35c4
    Closes-Bug: #1328831

[Dima Shulyak (dshulyak)]

All migrations was squashed in one 5.1 migration.

[Evgeniy L (rustyrobot)]

Removing from 5.0.1 release since we don't have migration changes in maintenance releases.

https://bugs.launchpad.net/fuel/+bug/1335088