Make "clone()" public on every derived exception.
Make "clone()" public on every derived exception.

	* src/scheduler/exception.hh (COMPLETE_EXCEPTION): Make
	"clone" public. Otherwise, a particular instance could
	make it private and it would only be callable through
	a base type conversion.

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