CBQE-0 fix monitor DCP upgrade test

Change-Id: I378153fc0c11c33333d21662b61eb4c15471a59f
Reviewed-on: http://review.couchbase.org/40814
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: Thuan Nguyen <soccon@gmail.com>