Ceph

Nose has been abandoned by upstream for quite some time¹, and has already
caused at least one bug with reproducable failures².

We should stop making use of it and switch to either plain unittest or pytest.

% git grep -c 'from nose'
doc/radosgw/session-tags.rst:1
src/test/pybind/test_ceph_argparse.py:1
src/test/pybind/test_cephfs.py:1
src/test/pybind/test_rados.py:3
src/test/pybind/test_rbd.py:2
src/test/pybind/test_rgwfs.py:1
src/test/rgw/bucket_notification/test_bn.py:3
src/test/rgw/rgw_multi/tests.py:3
src/test/rgw/rgw_multi/tests_az.py:2
src/test/rgw/rgw_multi/tests_es.py:1
src/test/rgw/rgw_multi/tests_ps.py:2
src/test/rgw/rgw_multi/zone_cloud.py:1
src/test/rgw/rgw_multi/zone_es.py:1
src/test/rgw/rgw_multi/zone_rados.py:1

% git grep -ce '-m nose'
qa/workunits/fs/test_python.sh:1
qa/workunits/rados/test_python.sh:1
qa/workunits/rbd/test_librbd_python.sh:2
qa/workunits/rgw/run-s3tests.sh:1
src/test/pybind/CMakeLists.txt:2
src/test/rgw/bucket_notification/README.rst:2
src/test/run-rbd-tests:1

1: https://github.com/nose-devs/nose/issues/1099#issuecomment-562394879
2: https://tracker.ceph.com/issues/53478