Have at least 1 unit test with high priority bucket

Change-Id: Icc92c9455c13ca1af21eb285c72b8a8f3555cf6b
Reviewed-on: http://review.couchbase.org/40313
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Sundararaman Sridharan <sundar@couchbase.com>