MB-100: small scale reb vperf conf

Change-Id: I8a2de3880d2455c56d266a890dafdcddb0f03581
Reviewed-on: http://review.couchbase.org/24254
Reviewed-by: Ronnie Sun <ronnie@couchbase.com>
Tested-by: Ronnie Sun <ronnie@couchbase.com>