CBD-1191: Fix typo for healthchecker

Change-Id: Icf89bc3cacfdf898c94aaaf8c3c1cd1bc9dbb9b5
Reviewed-on: http://review.couchbase.org/33823
Reviewed-by: Eric Limare <eric.limare@couchbase.com>
Tested-by: Eric Limare <eric.limare@couchbase.com>
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>