fix task.owner to be nullable=False in models.py

[Nikhil Komawar]

We currently, do not allow NULL owner for tasks and models.py lets it be NULL however, the tasks table ensures that it does not set NULL owner.

So, we do not need migration - just need fix in the code patch for this.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/60330

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/60330
Committed: http://github.com/openstack/glance/commit/21cfc3f465f18a030878032477ec255421a2e8dc
Submitter: Jenkins
Branch: master

commit 21cfc3f465f18a030878032477ec255421a2e8dc
Author: Nikhil Komawar <email address hidden>
Date: Thu Dec 5 13:57:05 2013 -0500

    Makes tasks owner not nullable in models.py

    The tasks table scheme in migration for adding tasks to Glance DB has a
    flag for disabling from setting a NULL owner.

    In order to keep the behavior consistent across the glance codebase,
    this patch adds owner as not nullable in the models.py.

    Fixes bug: 1257949

    Change-Id: Id9fff4277f427b7d83d80b5a0a8029968f70e0df