referred/in-use L3policy deletion does not fail

[puppet-py]

If a L3policy(default/user-created) is referred by a L2policy, we are allowing the Delete of the L3policy, although the L2policy is still using that L3policy

Please find the steps to bug:

test@localhost:~/devstack$ gbp l2policy-create L2-vlan-A
Created a new l2_policy:
+----------------------+--------------------------------------+
| Field | Value |
+----------------------+--------------------------------------+
| description | |
| id | f7b990dc-ab1b-4a3a-a3ea-6a0a54ada2ba |
| l3_policy_id | 117b8e43-71c2-48f4-be9b-e5bb35f5af1b |
| name | L2-vlan-A |
| network_id | 2074f61b-9982-4109-b403-99c5fb3a1e0a |
| policy_target_groups | |
| shared | False |
| tenant_id | 3b4eb7e4327b4d90be39288b2e8dd163 |
+----------------------+--------------------------------------+
test@localhost:~/devstack$
test@localhost:~/devstack$
test@localhost:~/devstack$ gbp l2policy-list
+--------------------------------------+-----------+-------------+--------------------------------------+
| id | name | description | l3_policy_id |
+--------------------------------------+-----------+-------------+--------------------------------------+
| f7b990dc-ab1b-4a3a-a3ea-6a0a54ada2ba | L2-vlan-A | | 117b8e43-71c2-48f4-be9b-e5bb35f5af1b |
+--------------------------------------+-----------+-------------+--------------------------------------+
test@localhost:~/devstack$
test@localhost:~/devstack$ gbp l3policy-list
+--------------------------------------+---------+------------------------------+------------+----------------------+
| id | name | description | ip_pool | subnet_prefix_length |
+--------------------------------------+---------+------------------------------+------------+----------------------+
| 117b8e43-71c2-48f4-be9b-e5bb35f5af1b | default | Implicitly created L3 policy | 10.0.0.0/8 | 26 |
+--------------------------------------+---------+------------------------------+------------+----------------------+
test@localhost:~/devstack$
test@localhost:~/devstack$ gbp l3policy-delete 117b8e43-71c2-48f4-be9b-e5bb35f5af1b <<<<< This SHOULD NOT BE ALLOWED
Deleted l3_policy: 117b8e43-71c2-48f4-be9b-e5bb35f5af1b
test@localhost:~/devstack$
test@localhost:~/devstack$
test@localhost:~/devstack$ gbp l3policy-list

test@localhost:~/devstack$
test@localhost:~/devstack$ gbp l2policy-list
+--------------------------------------+-----------+-------------+--------------+
| id | name | description | l3_policy_id |
+--------------------------------------+-----------+-------------+--------------+
| f7b990dc-ab1b-4a3a-a3ea-6a0a54ada2ba | L2-vlan-A | | |
+--------------------------------------+-----------+-------------+--------------+
test@localhost:~/devstack$

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/155504

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/155504
Committed: https://git.openstack.org/cgit/stackforge/group-based-policy/commit/?id=8922c5ffb9f686ca56bfc1f4a6f31e5d4e5623cf
Submitter: Jenkins
Branch: master

commit 8922c5ffb9f686ca56bfc1f4a6f31e5d4e5623cf
Author: Robert Kukura <email address hidden>
Date: Wed Feb 11 17:07:00 2015 -0500

    Reject deletion of in-use L2Policy or L3Policy

    Before deleting an L2Policy, check that no PolicyTargetGroups
    reference it. Before deleting an L3Policy, ensure that no L2Policies
    reference it. Raise exceptions if they are in-use.

    Closes-bug: 1415244
    Closes-bug: 1407323

    Change-Id: Ie5d3c8a01a57a331eed46354c80ed28acad0fd04

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/juno
Review: https://review.openstack.org/160947

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/160947
Committed: https://git.openstack.org/cgit/stackforge/group-based-policy/commit/?id=cd45d0ea276cec6153f3e379ede8a34318e03ee5
Submitter: Jenkins
Branch: stable/juno

commit cd45d0ea276cec6153f3e379ede8a34318e03ee5
Author: Robert Kukura <email address hidden>
Date: Wed Feb 11 17:07:00 2015 -0500

    Reject deletion of in-use L2Policy or L3Policy

    Before deleting an L2Policy, check that no PolicyTargetGroups
    reference it. Before deleting an L3Policy, ensure that no L2Policies
    reference it. Raise exceptions if they are in-use.

    Closes-bug: 1415244
    Closes-bug: 1407323

    Change-Id: Ie5d3c8a01a57a331eed46354c80ed28acad0fd04
    (cherry picked from commit 8922c5ffb9f686ca56bfc1f4a6f31e5d4e5623cf)