common/perf_counters: When perf dump, using count instead of avgcount.

Actualy, the filed of avgcount don't do average. Don't ambiguous.

Signed-off-by: Ma Jianpeng <jianpeng.ma@intel.com>
ReplicatedPG: record correctly subop for perfcounter.

In log_subop_stats, it omit to record the counter of subop.

Signed-off-by: Ma Jianpeng <jianpeng.ma@intel.com>
ReplicatedPG: Make perfcounter record the read-size for async-read.

Signed-off-by: Ma Jianpeng <jianpeng.ma@intel.com>