moved capi_frontend:attempt into menelaus_web_crud

Where it belongs

Change-Id: I1431344131f3a6a3d3d75a3cd5d51da3325b05ed
Reviewed-on: http://review.couchbase.org/33178
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>