Gangs on Prowl in Storm-Wracked Haiti GONAIVES, Haiti - Victims who lost relatives, homes and belongings in Tropical Storm Jeanne are now tormented by street gangs who attack food convoys, raid homes at night and shoot those who get in their way.    The failure of Haiti's U.S.-backed government to disarm the gangs that helped oust President Jean-Bertrand Aristide has created a climate of instability that further jeopardizes lives after the calamity Jeanne visited on Gonaives 10 days ago...