Merge branch '5.1'

* 5.1:
  In the new authenticator system, no auth listener is valid

src/Symfony/Bundle/SecurityBundle/DependencyInjection/SecurityExtension.php

@@ -604,7 +604,7 @@ class SecurityExtension extends Extension implements PrependExtensionInterface
             }
         }
 
-        if (false === $hasListeners) {
+        if (false === $hasListeners && !$this->authenticatorManagerEnabled) {
             throw new InvalidConfigurationException(sprintf('No authentication listener registered for firewall "%s".', $id));
         }