CBQE-2172 fix healthchecker test code

Change-Id: Ia6302b05ffa7ed0797201cd9f50bf118f85c68fe
Reviewed-on: http://review.couchbase.org/35226
Tested-by: Thuan Nguyen <soccon@gmail.com>
Reviewed-by: Tommie McAfee <tommie@couchbase.com>