Comment 20 for bug 1591976

Reviewed: https://review.opencontrail.org/22852
Committed: http://github.org/Juniper/contrail-controller/commit/3008c4333e73605142c22c11d9ca853499d70cf0
Submitter: Zuul
Branch: R3.1

commit 3008c4333e73605142c22c11d9ca853499d70cf0
Author: Édouard Thuleau <email address hidden>
Date: Mon Aug 1 18:00:21 2016 +0200

[VNC OpenStack] Remove stale security group rules

When a security group is deleted all security group rules which
reference it as 'remote_group_id' should be deleted.
As the contrail data model does not permit to easy found that rules,
that fix propose to clean that stale rules only when they are listed or
read.

[1] https://github.com/openstack/tempest/search?utf8=%E2%9C%93&q=test_security_group_rules_delete_when_peer_group_deleted&type=Code

Change-Id: Ifcd39f7f7b04c07cb6d4b62aa8aa90007f8bc81d
Closes-Bug: #1591976
(cherry picked from commit ad6a675556ec8bcbd53e9705e1a748ff0f866b00)