OE stablished from WEST to EAST; WEST down OE; the delete OE interface

It shouldn't crash:

- ipsec down '"private-or-clear#192.1.2.0/24"'

  this takes down and deletes the OE instantiations (1) and leaves the
  OE template

- ifconfig eth1 down

- ipsec listen

  This should delete '"private-or-clear#192.1.2.0/24"' since it has
  not interface; and then instantiate OE template connections for any
  new interfaces.

- ifconfig eth1 up

- ipsec listen

  bonus points if the groups are re-expanded, oriented, and routed
  with the restored interface

see #2413 FATAL: ASSERTION FAILED: ...
