CBQE-1175: use direct mc client for kv latency

replacing previous functionality that relied on underlying sdk,
as latency can be misleading based on implementation.

Change-Id: I62e98c60aab05b3b077a11934e466552b59d4ef5
Reviewed-on: http://review.couchbase.org/25401
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Tommie McAfee <tommie@couchbase.com>
CBQE-1181: ignore tmp_oom errs in sdk

occurs when out of memory.  we should be able to track this by looking at(plotting) 'ep_tmp_oom_errors'.
ignore as in do not print to output.

Change-Id: Ied7bd0471c1d8b758f404286809daacb02461b90
Reviewed-on: http://review.couchbase.org/25403
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Chisheng Hong <chisheng@couchbase.com>
Tested-by: Chisheng Hong <chisheng@couchbase.com>