cleancode: clean code for utils_linux.go
cleancode: clean code for utils_linux.go

Signed-off-by: Jeff Zvier <71e8b602e9d0c167f5a66002d8479f3199ddfca9@gmail.com>

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