CBQE-2190:: Fix testrunner failure in task.py

Change-Id: I126348321391ee97a60cdf7c0b422f6250911ea2
Reviewed-on: http://review.couchbase.org/35523
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Thuan Nguyen <soccon@gmail.com>
Reviewed-by: Parag Agarwal <agarwal.parag@gmail.com>
Tested-by: Parag Agarwal <agarwal.parag@gmail.com>