CBQE-0 increase items loaded to
speed up the bucket into 80% dgm

Change-Id: Ib051290ea10508aa167077a8e0793a7b55c660ae
Reviewed-on: http://review.couchbase.org/33474
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: Thuan Nguyen <soccon@gmail.com>