Simplify and optimize Object::slot_get.
Simplify and optimize Object::slot_get.

	* src/object/object.cc: Now that slot locate also returns the slot, no
	use to search the hash table twice.

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