By Lamine Chikhi and Myra MacDonald ALGIERS (Reuters) - Three weeks after being rushed to hospital in Paris, Algerian President Abdelaziz Bouteflika has disappeared from sight, leaving behind a country preparing for a successor who for the first time will come from a generation too young to have fought in Algeria's war of independence against France. In a country run with Soviet-style secrecy, nobody is sure how sick Bouteflika is. ...