Revert "MB-11846: Un-disable optimization as it ..."

This reverts commit 2be3904d62349463c45ef97806df37298db96149.

Change-Id: Ice24eed2620378b83372c0725fca7e2f464a87dc
Reviewed-on: http://review.couchbase.org/40164
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>