MB-100: fix XDCR_LATENCY_OPTIMIZATION parameter

Change-Id: Iae526306d3022daaf90f0df9c7c4b12d239a0257
Reviewed-on: http://review.couchbase.org/24765
Reviewed-by: Pavel Paulau <pavel.paulau@gmail.com>
Tested-by: Pavel Paulau <pavel.paulau@gmail.com>