Update to Symfony 2.5

* Issue: https://www.drupal.org/node/2278353
* Commit: https://github.com/drupal/drupal/commit/a21acb3b7dc1dda5880a225321b3e1109dcf00c1
Merge pull request #210 from jmolivas/update-symfony-2.5.0

Update to Symfony 2.5