CIMI - Tests - modfiying test_helper.rb cleanup code to work with Openstack provider

TrackedAt: http://tracker.deltacloud.org/patch/1e5a6656b4f4eeaf278bf60efd812b9bf9682611
CIMI - Tests - test_helper.rb minor change to cleanup code

TrackedAt: http://tracker.deltacloud.org/patch/14563fd62985833eb53ffc2c3c724cc113d975f0