MB-10808: Restore distinction between BIN_PREFIX and DATA_PREFIX

Change-Id: Iccb3f65ea9f6973f6fd4931eb7febe84fb3b855d
Reviewed-on: http://review.couchbase.org/36722
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>