Make sure the VLAN interfaces as well as its rules will be removed prior
to the actual/parent interface.
The VLAN configs are gone in vlan_post_stop() already so we have to use
vlan_pre_stop() instead.
Reported-by: Bernd Bednarz <bernd.bednarz@avira.com>
X-Gentoo-Bug: 380603
X-Gentoo-Bug-URL: https://bugs.gentoo.org/380603