dump tag counts
ReplicatedPG: use ReplicatedPGRef for C_OSD_OpApplied

Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG: use ReplicatedPGRef for C_OSD_OpCommit

Signed-off-by: Samuel Just <sam.just@inktank.com>
RepModify tag
ReplicatedPG: use ReplicatedPGRef for C_PG_MarkUnfoundLost

Signed-off-by: Samuel Just <sam.just@inktank.com>