This is a direct commit to stable/11 however it performs MFC r366857
applied to stable/12 with r367049. This is due to src/etc/rc.d/netif
having been previously moved to src/libexec/rc.d/netif.

Destroy cloned interfaces at netif stop, netif restart and shutdown.
This is especially important during shutdown because a child interface
of lagg with WOL enabled will not enable WOL at interface shutdown and
thus no WOL to wake up the device (and machine).

PR: 158734, 109980
Reported by: Antonio Huete Jimenez <tuxillo at quantumachine.net>

		Marat N.Afanasyev <marat at zealot.ksu.ru>

reviewed by: kp