Fix use statement

DependencyInjection/SonataUserExtension.php

@@ -13,13 +13,10 @@ namespace Sonata\UserBundle\DependencyInjection;
 
 use Symfony\Component\Config\Definition\Processor;
 use Symfony\Component\DependencyInjection\Loader\XmlFileLoader;
-use Symfony\Component\Config\Resource\FileResource;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Reference;
-use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\HttpKernel\DependencyInjection\Extension;
 use Symfony\Component\Config\FileLocator;
-use Symfony\Component\Config\Definition\Processor;
 
 use Sonata\EasyExtendsBundle\Mapper\DoctrineCollector;