MB-11184: use beforeNotify to override request

Change-Id: Ic3abbbe4b4a947a635cd50e9b955f25311fa7bd1
Reviewed-on: http://review.couchbase.org/38406
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>