fix process kill

Author: Grzegorz Marszalek

runner/util_linux.go

@@ -31,6 +31,9 @@ func (e *Engine) killCmd(cmd *exec.Cmd) (pid int, err error) {
 func (e *Engine) startCmd(cmd string) (*exec.Cmd, io.ReadCloser, io.ReadCloser, error) {
 	c := exec.Command("/bin/sh", "-c", cmd)
 	if e.config.Screen.NoPTY {
+		c.SysProcAttr = &syscall.SysProcAttr{
+			Setpgid: true,
+		}
 		stderr, err := c.StderrPipe()
 		if err != nil {
 			return nil, nil, nil, err