Merge PR #22596 into master

Merge PR #22596 into master

* refs/pull/22596/head:
	os/bluestore: use vector instead of set for zombies
	os/bluestore: reuse zombie OpSequencers by collection id
	qa/suites/rados/objecstore/backends/objectstore: capture coredumps
	os/bluestore: more debug output
	os/bluestore: print cnode from _open_collections
	os/bluestore: print cnode on fsck
	qa/suites/rados/objecstore: preserve data dir for ceph_test_objecstore

Reviewed-by: Igor Fedotov <ifedotov@suse.com>