add Definition support to YamlFileLoader::resolveServices

gistfile1.txt

diff --git a/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
index 71de4ac..ee9c589 100644
--- a/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+++ b/core/vendor/symfony/dependency-injection/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -306,6 +306,8 @@ private function resolveServices($value)
             }
 
             $value = new Reference($value, $invalidBehavior, $strict);
+        } elseif (is_string($value) &&  0 === strpos($value, '+')) {
+            $value = new Definition(substr($value, 1));
         }
 
         return $value;