unittest_pglog: fix unittest

This was broken by the pg_stat_t::reported cleanup.

Signed-off-by: Sage Weil <sage@inktank.com>
mon: do not scrub if scrub is in progress

This prevents an assert from unexpected scrub results from the previous
scrub on the leader.

Backport: cuttlefish
Signed-off-by: Sage Weil <sage@inktank.com>