basic OE test, ensuring road does not respond to acquires for its own IP address(es)

192.1.3.0/24 is in private-or-clear, so it should trigger OE attempts. But since
we are 192.1.3.209 and 192.1.3.210 ourselves, it should notice this and the pings
to ourselves should not trigger OE activity.

this test is xfrm specific
