Sgt. 1st Class Gregory Henson goes out on patrol with a computer on his back and a joystick in his holster. He also carries a rifle, but the military is hoping he’ll soon have less need for it. A wired generation of U.S. soldiers is about to battle-test a high-tech weapon calculated to reduce civilian casualties in Afghanistan. A key component is the “Dragon Egg,” a softball-sized robotic camera that can be thrown over a hill or into a building without endangering troops.