(CBD-1191): Update healthchecker script.

Change-Id: I5bf7b8295d181fcfe708e2c70f759fbe7d2725ed
Reviewed-on: http://review.couchbase.org/33507
Reviewed-by: Eric Limare <eric.limare@couchbase.com>
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>