libct/cg/fs/cpuacct: use fscommon.ReadFile
libct/cg/fs/cpuacct: use fscommon.ReadFile

Signed-off-by: Kir Kolyshkin <3a017b8ddb3f9cf3e4a59978b004111bdeb97f08@gmail.com>

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