Update DependencyInjection YamlFileLoader for Symfony 2.6

Reopening because #2366043: Upgrade to Symfony 2.6.0-beta1 did not take care of core/lib/Drupal/Core/DependencyInjection/YamlFileLoader.php which is a modified copy of the symfony YamlFileLoader.

Setting to needs work, because the patch in #1 contains unrelated hunks.

Reworked for the upgrade from 2.4 to 2.6.

I cannot reproduce #6.

Consider the bar service decorating foo in sites/default/services.yml:

services:
  foo:
    class: stdClass
  bar:
    public: false
    class: ArrayObject
    decorates: foo
    arguments: ["@bar.inner", "other-stuff"]

Produces the following code in the compiled container when the patch is applied:

    protected function getFooService()
    {
        return $this->services['foo'] = new \ArrayObject(new \stdClass(), 'other-stuff');
    }

In contrast without the patch, service decoration does not work (which is expected behavior):

    protected function getFooService()
    {
        return $this->services['foo'] = new \stdClass();
    }

+++ b/core/lib/Drupal/Core/DependencyInjection/YamlFileLoader.php
@@ -86,6 +86,10 @@ public function load($file)
+                throw new InvalidArgumentException(sprintf('The "parameters" key should contain an array in %s. Check your YAML syntax.', $resource));

There is no $resource here, use $file instead.