NCBC-665: Significant regression in memcached ops

This patch fixes a regression but that was introduced in commit
48023fad3d73192e26dc5df0f570e6e1757a21a2.

Change-Id: Icb10d902f7574b4e6c4133d107ded501feb7eebd
Reviewed-on: http://review.couchbase.org/41851
Tested-by: Jeffry Morris <jeffrymorris@gmail.com>
Reviewed-by: Brett Lawson <brett19@gmail.com>