OKLAHOMA CITY — Warriors center David West is an anomaly in a league in which the average career spans less than five years. In his 15th NBA season, West, 37, is not only still hanging around, he’s getting better. “We call him Benjamin Button,” point guard Shaun Livingston said. “He’s aging backward.” West’s minutes are down slightly from last season, but he is averaging more points, rebounds and blocks per game.