Issue 5019 - Fixes anti adblock notification not being added on first run

lib/antiadblockInit.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 68 matching lines @@
   );
   if (antiAdblockSubscription.lastDownload && antiAdblockSubscription.disabled)
     addAntiAdblockNotification(antiAdblockSubscription);
 
   function onSubscriptionChange(subscription)
   {
     let url = Prefs.subscriptions_antiadblockurl;
     if (url != subscription.url)
       return;
 
-    if (url in FilterStorage.knownSubscriptions && !subscription.disabled)
+    if (url in FilterStorage.knownSubscriptions && subscription.disabled)
       addAntiAdblockNotification(subscription);
     else
       removeAntiAdblockNotification();
   }
 
   FilterNotifier.on("subscription.updated", onSubscriptionChange);
   FilterNotifier.on("subscription.removed", onSubscriptionChange);
   FilterNotifier.on("subscription.disabled", onSubscriptionChange);
 };