The code has already called VariantClear() which has released the
interface yet not set it to NULL.  This is to prevent a double-release
after a forthcoming patch to WdtpInterfacePointer_UserUnmarshal().
Signed-off-by: Huw Davies <huw@codeweavers.com>
Signed-off-by: Alexandre Julliard <julliard@winehq.org>