CBQE-1473 print out stats every 5 minutes in stead of 1

Change-Id: I9f75368e72367cf24b70f30b3a165f8465c28a1e
Reviewed-on: http://review.couchbase.org/27590
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Thuan Nguyen <soccon@gmail.com>