[TwigBundle] always load the exception listener if the templating.engines is not present

Author: fabpot

DependencyInjection/Compiler/ExceptionListenerPass.php

@@ -28,9 +28,11 @@ public function process(ContainerBuilder $container)
         }
 
         // register the exception controller only if Twig is enabled
-        $engines = $container->getParameter('templating.engines');
-        if (!in_array('twig', $engines)) {
-            $container->removeDefinition('twig.exception_listener');
+        if ($container->hasParameter('templating.engines')) {
+            $engines = $container->getParameter('templating.engines');
+            if (!in_array('twig', $engines)) {
+                $container->removeDefinition('twig.exception_listener');
+            }
         }
     }
 }