Issue #1641166 by Schnitzel: Fixed Undefined property:...

Issue #1641166 by Schnitzel: Fixed Undefined property: Drupal\Core\Language\Language:: in language_list().

core/lib/Drupal/Core/Language/Language.php

@@ -24,6 +24,7 @@ class Language {
   public $weight = 0;
   public $default = FALSE;
   public $method_id = NULL;
+  public $locked = FALSE;
 
   /**
    * Language constructor builds the default language object.