unabled to remove security groups from ports

[Aaron Rosen]

After this patch 26332dcb merged in quantum quantum port-update <id> --security_groups=None no longer works.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/20967

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/20967
Committed: http://github.com/openstack/python-quantumclient/commit/dad11b3e757d459f9afed5b4b65b74a86362dbd5
Submitter: Jenkins
Branch: master

commit dad11b3e757d459f9afed5b4b65b74a86362dbd5
Author: Aaron Rosen <email address hidden>
Date: Thu Jan 31 19:54:11 2013 -0800

    Allow ability to remove security groups from ports

    This commit adds the option --no-security-groups to port-update
    in order to remove security groups from a port.

    Fixes bug 1112089

    Change-Id: I43a5cc2c8b443f2d34fffe66b442925a5ae312ac