Add testing of Neutron per tenant quotas API

The following is added to the Neutron (aka Quantum) API tests:

1) Update to rest client to include methods to invoke the per tenant quotas
API extension as specified in:

http://docs.openstack.org/api/openstack-network/2.0/content/quotas_ext.html

2) New test case to exercise the per tenant quotas API extension

Change-Id: I36df078b51d18c41bf9d9e32a82a073b71128092
Merge "Add testing of Neutron per tenant quotas API"