rados/singleton-nomsgr/all/objectstore: clean up

ceph_test_objectstore scribbles in $CWD.  Keep it inside $TESTDIR and
clean up when we are done.

Fixes: #8395
Signed-off-by: Sage Weil <sage@inktank.com>
rados/singleton-nomsgr/all/objectstore: skip ceph cluster setup

Not necessary; we just need it installed.

Signed-off-by: Sage Weil <sage@inktank.com>
Merge pull request #36 from ceph/wip-objectstore

fix objecstore test