multi-version: do not run new ceph_test_rados against dumpling

Dumpling does not properly order reads (w/ RWORDERED) vs writes.  The code
controlling that was totally rewritten in firefly.  It's not worth backporting.

Signed-off-by: Sage Weil <sage@redhat.com>
Merge pull request #187 from ceph/wip-multi-version

multi-version: do not run new ceph_test_rados against dumpling