Issue 3334 - Fix warnings spotted during testing before release

lib/whitelisting.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2015 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 52 matching lines @@
 
     if (filter)
       return true;
 
     frame = parent;
   }
 
   return false;
 };
 
+let getKey =
 /**
  * Gets the public key, previously recorded for the given page
  * and frame, to be considered for the $sitekey filter option.
  *
  * @param {Page}  page
  * @param {Frame} frame
  * @return {string}
  */
 exports.getKey = function(page, frame)
 {
@@ skipping 50 matching lines @@
 {
   if (token.indexOf("_") < 0)
     return;
 
   let [key, signature] = token.split("_", 2);
   key = key.replace(/=/g, "");
 
   if (verifyKey(key, signature, frame.url))
     recordKey(page, frame.url, key);
 };