osd/ReplicatedPG: no HitSet on non-primary

Signed-off-by: Sage Weil <sage@inktank.com>
mon/OSDMonitor: simplify and make 'osd pool set ...' output consistent

Signed-off-by: Sage Weil <sage@inktank.com>
Merge pull request #1079 from ceph/wip-tier-bits

osd: a few tiering fixes

Reviewed-by: Greg Farnum <greg@inktank.com>