fixing replicate/persist latency collector
fixing replicate/persist latency collector

Change-Id: I8e9f5fa4ff6a68f9dcdcdf6bdc4ef3fa2cf1cb6b
Reviewed-on: http://review.couchbase.org/c/perfrunner/+/147943
Tested-by: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Bo-Chun Wang <bb86fd206c9c35341feb9b50e74a74a83e254d63@couchbase.com>

couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner,couchbase/perfrunner