CBQE-1259 fix the bug due to fitting test automation on MAC platform

Change-Id: If9e76e19227c281bc7b8bab313bc2e2b888357b0
Reviewed-on: http://review.couchbase.org/26250
Reviewed-by: Chisheng Hong <chisheng@couchbase.com>
Tested-by: Chisheng Hong <chisheng@couchbase.com>