FWaaS plugin should allow creating only one firewall per tenant

[Sumit Naiksatam]

The reference implementation of the FWaaS iptables agent/driver supports only one firewall per tenant in Havana release. However, the FWaaS plugin will let you create more than one firewall. This should not be allowed since it creates an inconsistent state with only the most recent policy being applied.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/47659

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/47659
Committed: http://github.com/openstack/neutron/commit/78aa12567d226fe73df483d75e0d1980e6d3625e
Submitter: Jenkins
Branch: master

commit 78aa12567d226fe73df483d75e0d1980e6d3625e
Author: Sumit Naiksatam <email address hidden>
Date: Fri Sep 20 16:40:52 2013 -0700

    Fix FWaaS plugin to allow one firewall per tenant

    The reference implementation of the FWaaS iptables
    agent/driver supports only one firewall per tenant
    in Havana release. However, the FWaaS plugin will
    let you create more than one firewall. This is
    being fixed in this patch to not allow creating
    the second firewall if a firewall already exists
    for the tenant.

    Change-Id: I8f1cad9791723ba919b5774a63982c204686ddfe
    Closes-Bug: #1228442