Remove mox from nova/tests/unit/virt/xenapi/test_driver.py
Remove mox from nova/tests/unit/virt/xenapi/test_driver.py

Replace stubs.Set() with mock.patch.object
Replace mox.stubOutWithMock() with mock.patch

Part of blueprint remove-mox-ocata

Change-Id: I8e6e1fd44c884a25710f27777fa462fcdfca92a7

Juniper/nova,gooddata/openstack-nova,openstack/nova,rahulunair/nova,mahak/nova,rajalokan/nova,rajalokan/nova,klmitch/nova,gooddata/openstack-nova,Juniper/nova,mikalstill/nova,vmturbo/nova,openstack/nova,gooddata/openstack-nova,hanlind/nova,gooddata/openstack-nova,jianghuaw/nova,jianghuaw/nova,vmturbo/nova,mikalstill/nova,openstack/nova,mikalstill/nova,rahulunair/nova,rajalokan/nova,klmitch/nova,rajalokan/nova,klmitch/nova,rahulunair/nova,mahak/nova,klmitch/nova,hanlind/nova,vmturbo/nova,jianghuaw/nova,mahak/nova,jianghuaw/nova,phenoxim/nova,hanlind/nova,phenoxim/nova,Juniper/nova,vmturbo/nova,Juniper/nova