Merge branch '5.1'

* 5.1: (36 commits)
  Fixed left-over debug statement
  set column length for mysql 5.6 compatibility
  [Mime] Remove unused var
  [HttpClient] fix monitoring timeouts when other streams are active
  [PhpUnitBridge] fix syntax on PHP 5.3
  [PhpUnitBridge] Fix undefined index when output of "composer show" cannot be parsed
  properly cascade validation to child forms
  [PropertyAccess] Fix getter call order BC
  [PhpUnitBridge] fix undefined var on version 3.4
  Fix invalid char in SQS Headers
  Move ajax clear event listener initialization on loadToolbar
  [HttpClient] Throw JsonException instead of TransportException on empty response in Response::toArray()
  Fix CS
  FrameworkBundle Serializer issue
  register event listeners depending on the installed packages
  take into account the context when preserving empty array objects
  Only register CSRF protection listener if CSRF is available
  [VarExporter] tfix: s/markAsSkipped/markTestSkipped/
  Also check PUBLIC_ACCESS for authenticated tokens
  Fix enabled_locales behavior
  ...

Author: nicolas-grekas

DependencyInjection/FrameworkExtension.php

@@ -1094,7 +1094,7 @@ private function registerTranslatorConfiguration(array $config, ContainerBuilder
         $defaultOptions['cache_dir'] = $config['cache_dir'];
         $translator->setArgument(4, $defaultOptions);
 
-        $translator->setArgument(6, $config['enabled_locales']);
+        $translator->setArgument(5, $config['enabled_locales']);
 
         $container->setParameter('translator.logging', $config['logging']);
         $container->setParameter('translator.default_path', $config['default_path']);
@@ -1379,7 +1379,7 @@ private function registerAnnotationsConfiguration(array $config, ContainerBuilde
 
     private function registerPropertyAccessConfiguration(array $config, ContainerBuilder $container, XmlFileLoader $loader)
     {
-        if (!class_exists('Symfony\Component\PropertyAccess\PropertyAccessor')) {
+        if (!class_exists(PropertyAccessor::class)) {
             return;
         }
 
@@ -1463,7 +1463,7 @@ private function registerSerializerConfiguration(array $config, ContainerBuilder
 
         $chainLoader = $container->getDefinition('serializer.mapping.chain_loader');
 
-        if (!class_exists('Symfony\Component\PropertyAccess\PropertyAccessor')) {
+        if (!class_exists(PropertyAccessor::class)) {
             $container->removeAlias('serializer.property_accessor');
             $container->removeDefinition('serializer.normalizer.object');
         }
@@ -1472,7 +1472,7 @@ private function registerSerializerConfiguration(array $config, ContainerBuilder
             $container->removeDefinition('serializer.encoder.yaml');
         }
 
-        if (!class_exists(UnwrappingDenormalizer::class)) {
+        if (!class_exists(UnwrappingDenormalizer::class) || !class_exists(PropertyAccessor::class)) {
             $container->removeDefinition('serializer.denormalizer.unwrapping');
         }