OSD perfcounter: implement existing counter calculate

Although sub_op_*(pull/push) are deprecated op and we can delete these
counter, here consider to supply existing counter support for it.

Signed-off-by: Haomai Wang <haomaiwang@gmail.com>
OSD perfcounter: implement pull/push perf counter

Here consider to only count MOSDPGPull and MOSDPush message and exclude sub
op.

Signed-off-by: Haomai Wang <haomaiwang@gmail.com>