osd/ReplicatedPG: remove debug lines from snapset_context get/put

The dout() prefix does get_osdmap(), which requires (and asserts) that we
hold the pg lock, but in some cases we do not, notably
ReplicatedPG::object_context_destructor_callback.

Signed-off-by: Sage Weil <sage@inktank.com>
osd/ReplicatedPG: drop dout from object_context_destructor_callback

We don't hold the pg lock; cannot call dout here.

Signed-off-by: Sage Weil <sage@inktank.com>
ceph_test_rados: rollback bumps user_version

Sigh.  This doesn't make much intuitive sense to me, but this is how it
currently works.

Switch to using the async api while we are at it.

Signed-off-by: Sage Weil <sage@inktank.com>
Merge pull request #559 from ceph/wip-osd-rollback

fixes a few osd dout bugs; make rados model behave with rollback

Reviewed-by: Samuel Just <sam.just@inktank.com>