Fix assertItemsEqual usage for py3
Fix assertItemsEqual usage for py3

assertItemsEqual is not present in python 3 so
we should use six.assertCountEqual for compatibilty
between python 2 and 3.

Change-Id: I0e6c35e0ae033c1669bb978050a7899491edcba8

sebrandon1/tempest,Tesora/tesora-tempest,cisco-openstack/tempest,openstack/tempest,Tesora/tesora-tempest,openstack/tempest,Juniper/tempest,masayukig/tempest,sebrandon1/tempest,masayukig/tempest,Juniper/tempest,cisco-openstack/tempest,vedujoshi/tempest,vedujoshi/tempest