added FilesystemIterator namespace

src/Symfony/Bundle/FrameworkBundle/Util/Filesystem.php

@@ -102,7 +102,7 @@ class Filesystem
             }
 
             if (is_dir($file) && !is_link($file)) {
-                $fi = new FilesystemIterator($file);
+                $fi = new \FilesystemIterator($file);
                 foreach($fi as $item) {
                     $this->remove($item->getPathname());
                 }