An armed man who tried to carjack a motorist at a DeKalb County gas station Sunday was killed when the motorist shot at him, police said.DeKalb police said the would-be carjacker, Banarrek Von Clayton, 28, was shot in the leg and later died at Grady Memorial Hospital.The motorist, Brian Dean, 24, told police he was at a gas station in the 4300 block of Glenwood Road at about 3 a.m. when Clayton approached him and threatened him with a gun.Dean then took out his gun and shot Clayton in the leg, said Sgt. Willie Durrett.Clayton was able to drive off...