TAIPEI — One down. One more to go? That was the question being asked by China watchers following the relatively lenient 15-year prison sentence doled out to a former protégé of disgraced political heavyweight Bo Xilai on Monday. Wang Lijun, 52, a once high-flying police chief — who set off China’s most gripping political scandal in decades by walking into the US consulate in Chengdu with tales of murder, extortion and corruption — was found guilty of defection, abuse of power, taking bribes and bending the law for personal gain.