Comment 3 for bug 1840965

I'm attaching a patch for dhclient-enter-hooks.d/config.
I thought to imitate ipconfig and write all values even if they're empty.

For the debian/dhclient-script.* scripts which use chmod/chown parameters that aren't available in busybox, it might be best to just omit them, or use `cp/rm` instead of `chown/mv`.
`cp` is supposed to preserve target attributes etc, so it'll work in a real system, even if `busybox cp` doesn't do that.