Fix tox.ini to run tests in lockutils wrapper.
Fix tox.ini to run tests in lockutils wrapper.

Without this line locks while parallel tests running won't be
working and there will be tests fails because of this.

Change-Id: I5d29441365fafd8005ac9a2088badca23bf7cb09

frossigneux/blazar,ChameleonCloud/blazar,openstack/blazar,ChameleonCloud/blazar,stackforge/blazar,paramite/blazar,frossigneux/blazar,openstack/blazar,stackforge/blazar,paramite/blazar,frossigneux/blazar