PYEONGCHANG, SOUTH KOREA?Here?s the problem facing Shani Davis: He?s not fast enough any more to skate away from this.He used to be, winning two gold and two silver speedskating medals in the Olympics, winning 11 titles at World Championships, breaking world records nine times, breaking barriers in a sport as white as the ice it races on. But he?s 35 now, and the engine doesn?t rev like it used to when he hits the gas.It didn?t Tuesday in the 1,500 metres, blazing to a quick opening 300 and then, nothing. His time...