Add WorflowGuardListenerPass only if it exists

Author: smnandre

src/Symfony/Bundle/FrameworkBundle/FrameworkBundle.php

@@ -168,7 +168,7 @@ public function build(ContainerBuilder $container)
         $container->addCompilerPass(new CachePoolClearerPass(), PassConfig::TYPE_AFTER_REMOVING);
         $container->addCompilerPass(new CachePoolPrunerPass(), PassConfig::TYPE_AFTER_REMOVING);
         $this->addCompilerPassIfExists($container, FormPass::class);
-        $container->addCompilerPass(new WorkflowGuardListenerPass());
+        $this->addCompilerPassIfExists($container, WorkflowGuardListenerPass::class);
         $container->addCompilerPass(new ResettableServicePass(), PassConfig::TYPE_BEFORE_OPTIMIZATION, -32);
         $container->addCompilerPass(new RegisterLocaleAwareServicesPass());
         $container->addCompilerPass(new TestServiceContainerWeakRefPass(), PassConfig::TYPE_BEFORE_REMOVING, -32);