s3tests: test list bucket versions
s3tests: test list bucket versions

Signed-off-by: Yehuda Sadeh <48638f9c2a62c4fd20be28d0bdad68f5cd041402@inktank.com>

dreamhost/s3-tests,timuralp/s3-tests,jmunhoz/s3-tests,Intel-bigdata/s3-tests,timuralp/s3-tests,ceph/s3-tests,ceph/s3-tests,tobegit3hub/s3-tests,andrewgaul/s3-tests,Intel-bigdata/s3-tests,dreamhost/s3-tests,smithfarm/s3-tests,robbat2/s3-tests,robbat2/s3-tests,smithfarm/s3-tests,jmunhoz/s3-tests,andrewgaul/s3-tests,tobegit3hub/s3-tests