Issue #1282156 by karschsp, kika: Convert IP-blocking table to 'Empty table pattern'.

core/modules/system/system.admin.inc

@@ -1373,6 +1373,7 @@ function system_ip_blocking($default_ip = '') {
     '#theme' => 'table',
     '#header' => $header,
     '#rows' => $rows,
+    '#empty' => t('No blocked IP addresses available.'),
   );
 
   return $build;