Noissue - Remove unnecessary references to undefined

lib/synchronizer.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present 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 268 matching lines @@
     lines.shift();
     let filters = [];
     for (let line of lines)
     {
       line = Filter.normalize(line);
       if (line)
         filters.push(Filter.fromText(line));
     }
 
     FilterStorage.updateSubscriptionFilters(subscription, filters);
-
-    return undefined;
   },
 
   _onDownloadError(downloadable, downloadURL, error, channelStatus,
                    responseStatus, redirectCallback)
   {
     let subscription = Subscription.fromURL(downloadable.url);
     subscription.lastDownload = Math.round(Date.now() / MILLIS_IN_SECOND);
     subscription.downloadStatus = error;
 
     // Request fallback URL if necessary - for automatic updates only
@@ skipping 49 matching lines @@
               subscription.filters.map(f => f.text).join("\n");
             redirectCallback("data:text/plain," + encodeURIComponent(data));
           }
         }, false);
         request.send(null);
       }
     }
   }
 };
 Synchronizer.init();