librados/TestCase: inheret cleanup_default_namespace

No need to duplicate this code.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 1d199fb1173dc9685dba96c22b83e4e9edf51a11)
ceph_test_rados_api: fix cleanup of cache pool

We can't simply try to delete everything in there because some items may
be whiteouts.  Instead, flush+evict everything, then remove overlay, and
*then* delete what remains.

Fixes: #9055
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit ebbe8aab17cfa2281902f167a706639535da4010)
ceph_test_rados_api_tier: fix cache cleanup (ec too)

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit d7fb7bf5f2059f411633751e376c2270e6040fba)
mon: fix divide by zero when pg_num adjusted and no osds

Fixes: #9101
Backport: firefly, dumpling
Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit d8fc22dea2228e23a7c12d0e311ee29b06425d6a)