Fix routing setup for SonataDoctrineAdminBundle

This fixes an error in the "Creating CMS using CMF and Sonata" tutorial
where it requires the routes in SonataDoctrinePhpcrAdminBundle/blob/master/Resources/config/routing/phpcrodmbrowser.xml to be included. It seems to related to the TODO within the
phpcrodmbrowser.xml file stating: `TODO: route only exists for Symfony2.1 compat
https://github.com/sonata-project/SonataDoctrinePhpcrAdminBundle/issues/86'