Lobby.onDisconnect: we no longer use handles.
Lobby.onDisconnect: we no longer use handles.

Fix issue #4400.

	* share/urbi/lobby.u: So don't even check for their type, since
	evaluation lobby.handle fires the code from uobject.u which
	defined lobby.handle as firing a warning.

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