test radosgw with command line interface

added swift-based tests for radosgw
Actually, although I think that nova-multi-controller and ceph-radosgw should be (by default) on the same node, I do not think it needs to affect this PR. 
Once we do the swift tests with keystone authentication, it is clear that radosgw is working, so we don't need to do those radosgw-admin tests.