Go에서 Ctrl C가 `exec.Command`를 중단하는 것을 어떻게 방지할 수 있나요?

package main

import (
    "log"
    "os"
    "os/exec"
    "os/signal"
    "syscall"
)

func sleep() {
    log.Println("Sleep start")
    cmd := exec.Command("sleep", "60")
    cmd.Run()
    log.Println("Sleep stop")
}

func main() {
    var doneChannel = make(chan bool)

    go sleep()

    c := make(chan os.Signal, 1)
    signal.Notify(c, os.Interrupt)
    signal.Notify(c, syscall.SIGTERM)
    go func() {
        <-c
        log.Println("Receved Ctrl + C")
    }()

    <-doneChannel
}

2015/10/16 10:05:50 Sleep start
^C2015/10/16 10:05:52 Receved Ctrl + C
2015/10/16 10:05:52 Sleep stop

cmd := exec.Command("sleep", "60")
cmd.SysProcAttr = &syscall.SysProcAttr{
    Setpgid: true,
}