CBQE-2315: add time out in test_employee_dataset_all_queries test

Change-Id: I1e9c409e71bf277fbea2aa66c8e94af6cfefac27
Reviewed-on: http://review.couchbase.org/39591
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>
Tested-by: Meenakshi Goel <meenakshi.goel@globallogic.com>
Reviewed-by: Meenakshi Goel <meenakshi.goel@globallogic.com>