CBQE-2304 add bin path to cwc base test

Change-Id: I12e72ae5f57df856bd61242bb4ab5887dabd3388
Reviewed-on: http://review.couchbase.org/39850
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Tested-by: Thuan Nguyen <soccon@gmail.com>