miniupnp commit c4991916e5c12a7754e935e71a5313e75af6aeb9 introduced a
4th statusCode parameter to miniwget function. This parameter is set
to a value returned by the UPnP device. We have to check if it's set
to 200 to make sure the result is a success. Also, we now have to check
if descXML is set in the error case and free it.
