fix readSync
fix readSync

Signed-off-by: SiYu Zhao <793bbd6e15f695d11331065015d03a0acd350282@gmail.com>

kolyshkin/runc,xiaochenshen/runc,kolyshkin/runc,opencontainers/runc,dqminh/runc,opencontainers/runc,mikebrow/runc,xiaochenshen/runc,mikebrow/runc,estesp/runc,rhatdan/runc,dqminh/runc,rhatdan/runc,opencontainers/runc,rhatdan/runc,estesp/runc,opencontainers/runc,rhatdan/runc,dqminh/runc,xiaochenshen/runc,dqminh/runc,estesp/runc,kolyshkin/runc,mikebrow/runc,kolyshkin/runc