removing unused use statement

Author: dbu

DependencyInjection/CmfTreeBrowserExtension.php

@@ -5,7 +5,6 @@
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\HttpKernel\DependencyInjection\Extension;
 use Symfony\Component\DependencyInjection\Reference;
-use Symfony\Component\DependencyInjection\ContainerInterface;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
 use Symfony\Component\DependencyInjection\Loader\XmlFileLoader;