Issue 2982 - Don't send notifications to users that were in the browser notification test

modules/notificationserver/files/site.conf

 keepalive_timeout 0;
 
 location /.hg
 {
   internal;
 }
 
 location /notification.json
 {
+  # Users that were in the browser notification test shouldn't see the same
+  # thing again, so they're not seeing any notifications for now.
+  # See https://issues.adblockplus.org/ticket/2982.
+  if ($arg_lastVersion ~ "-2/[1-3]")
+  {
+    rewrite ^ /empty-notification.json last;
+  }
+
   fastcgi_pass unix:/tmp/multiplexer-fastcgi.sock;
   include /etc/nginx/fastcgi_params;
   fastcgi_cache notification;
   fastcgi_cache_key $group;
   fastcgi_cache_valid any 1m;
   fastcgi_cache_lock on;
 }
+
+location /empty-notification.json
+{
+  root /var/www;
+}