don't pass -B and -r to memcached anymore

Because they're not needed and are going to be unsupported by
memcached soon.

Change-Id: I4c70b66986217c90784eed11d6716db190544133
Reviewed-on: http://review.couchbase.org/33148
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>