exec: Stdout already set

[jgbooks]

type CmdRunner struct {
	logger hclog.Logger
	cmd    *exec.Cmd

	stdout io.ReadCloser
	stderr io.ReadCloser

	// Cmd info is persisted early, since the process information will be removed
	// after Kill is called.
	path string
	pid  int

	addrTranslator
}

When executing the kill command to terminate a child process, I found that the runner did not close the stdout and stderr.