MB-100: revised reb large test

Change-Id: Ibefdc4355be8f5cce748322ac1a4a1c20ec9a5eb
Reviewed-on: http://review.couchbase.org/24411
Reviewed-by: Ronnie Sun <ronnie@couchbase.com>
Tested-by: Ronnie Sun <ronnie@couchbase.com>