Stop using mox stubs in volume/encryptors/test_base.py
Stop using mox stubs in volume/encryptors/test_base.py

Replace 'stubs.Set' with 'stub_out' in
nova/tests/unit/volume/encryptors/test_base.py

Change-Id: I6c671825062595444ab3331d648030546f8e791a
Implements: blueprint remove-mox-newton

Juniper/nova,sebrandon1/nova,gooddata/openstack-nova,cloudbase/nova,openstack/nova,klmitch/nova,klmitch/nova,cloudbase/nova,vmturbo/nova,klmitch/nova,jianghuaw/nova,rahulunair/nova,alaski/nova,hanlind/nova,alaski/nova,hanlind/nova,openstack/nova,jianghuaw/nova,gooddata/openstack-nova,gooddata/openstack-nova,rajalokan/nova,gooddata/openstack-nova,sebrandon1/nova,cloudbase/nova,rajalokan/nova,jianghuaw/nova,jianghuaw/nova,rajalokan/nova,rahulunair/nova,mahak/nova,hanlind/nova,vmturbo/nova,rahulunair/nova,phenoxim/nova,openstack/nova,Juniper/nova,vmturbo/nova,Juniper/nova,mahak/nova,Juniper/nova,vmturbo/nova,rajalokan/nova,phenoxim/nova,mikalstill/nova,mikalstill/nova,klmitch/nova,mikalstill/nova,mahak/nova,sebrandon1/nova