[sqlalchemy] clear_expired_metering_data didn't honor the newly added contraints

[Lianhao Lu]

The impl_sqlalchemy.Connection.clear_expired_metering_data() method was added quite some time ago, and it doesn't honor the following new added constraints :

- all metadata_xxx tables have foreign key constraints to meter.id
- alarm table has foreign key constraints to project.id and user.id.

[gordon chung (chungg)]

nice catch. i guess i should've put cascade on delete when i added metadata tables...

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/60995

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/60995
Committed: https://git.openstack.org/cgit/openstack/ceilometer/commit/?id=13764537a465b05b4d7fa864d30c81f7192d2490
Submitter: Jenkins
Branch: master

commit 13764537a465b05b4d7fa864d30c81f7192d2490
Author: Gordon Chung <email address hidden>
Date: Mon Dec 9 17:53:04 2013 -0500

    add newly added constraints to expire clear_expired_metering_data

    - cascade deletes to metadata tables on meter deletion
    - delete associations on object deletion
    - add check to not delete user/project entries associated with Alarm

    Change-Id: I24cbaea9ede6d142dc22eaf070b3f7d1f14b484a
    Closes-Bug: #1258071