Check for unused variables

Dirty hack to silence a warning that is already fixed in #18.

.jshintrc

@@ -15,7 +15,7 @@
   "nonew": true,
   "quotmark": "single",
   "undef": true,
-  "unused": false,
+  "unused": true,
   "strict": false,
 
   "node": true

ip_record.js

@@ -17,7 +17,7 @@ module.exports = function (BLOCK_INTERVAL_MS, INVALID_AGENT_INTERVAL_MS, now) {
   }
 
   function isBadAgent(agent) {
-    return false // TODO
+    return false && agent // TODO
   }
 
   IpRecord.prototype.isBlocked = function () {