PrimaryLogPG: reimplement osd_snap_trim_sleep within the state machine

PrimaryLogPG: reimplement osd_snap_trim_sleep within the state machine

Rather than blocking the main op queue, just pause for that amount of
time between state machine cycles.

Also, add osd_snap_trim_sleep to a few of the thrasher yamls.

Signed-off-by: Samuel Just <sjust@redhat.com>
(cherry picked from commit 2ed7759cfeb03e71f0fbd98fe7c2db2bb741861c)

Conflicts:
	src/osd/PrimaryLogPG.cc

Signed-off-by: Greg Farnum <gfarnum@redhat.com>
(cherry picked from commit 67336454a4cee66522bc0ca01b2c58b8960f75ec)

Conflicts:
	qa/suites/rados/thrash/thrashers/default.yaml
	qa/suites/rados/thrash/thrashers/pggrow.yaml
	src/osd/OSD.h
	src/osd/ReplicatedPG.cc
	src/osd/ReplicatedPG.h

Signed-off-by: Greg Farnum <gfarnum@redhat.com>