Issue 3829 - Use subscriptions.add instead add-subscriptions

subscriptionLink.postload.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 73 matching lines @@
     // Trim spaces in title and URL
     title = title.trim();
     url = url.trim();
     if (!/^(https?|ftp):/.test(url))
       return;
 
     ext.backgroundPage.sendMessage({
       type: "subscriptions.add",
       title: title,
       url: url,
-      ask: true
+      confirm: true
     });
   }, true);
 }