Added missing use statement

src/Symfony/Component/Config/Definition/BaseNode.php

@@ -13,6 +13,7 @@ namespace Symfony\Component\Config\Definition;
 
 use Symfony\Component\Config\Definition\Exception\Exception;
 use Symfony\Component\Config\Definition\Exception\ForbiddenOverwriteException;
+use Symfony\Component\Config\Definition\Exception\InvalidConfigurationException;
 
 /**
  * The base node class
@@ -259,4 +260,4 @@ abstract class BaseNode implements NodeInterface
      * @return mixed The finalized value
      */
     abstract protected function finalizeValue($value);
-}
+}