Replace use of mox with mock in test_ibm_xiv_ds8k
Replace use of mox with mock in test_ibm_xiv_ds8k

This patch replaces the remaining cases of mox with mock
in test_ibm_xiv_ds8k.py

Change-Id: Iea60cb3b47e1c25f30a6cfb4ba6451e6ac28fffa

bswartz/cinder,cloudbase/cinder,eharney/cinder,mahak/cinder,Hybrid-Cloud/cinder,bswartz/cinder,NetApp/cinder,openstack/cinder,j-griffith/cinder,j-griffith/cinder,cloudbase/cinder,openstack/cinder,ge0rgi/cinder,eharney/cinder,phenoxim/cinder,phenoxim/cinder,Datera/cinder,Datera/cinder,Nexenta/cinder,Hybrid-Cloud/cinder,Nexenta/cinder,mahak/cinder,NetApp/cinder