RTP: close listening UDP sockets on destruction.
RTP: close listening UDP sockets on destruction.

	* sdk-remote/src/uobjects/urbi/rtp.uob/rtp.cc: Store them,
	close them.

aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,aldebaran/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,urbiforge/urbi,aldebaran/urbi,urbiforge/urbi