Basic test of pluto using aggressive mode.

Test is otherwise identical to aggr-pluto-01, except now we are using
force_busy=yes to simulate a Denial of Service attack on east, which
should therefor be sending us cookies, with which we need to reply.

"westnet-eastnet": 192.0.1.0/24===192.1.2.45[@west]...192.1.2.23[@east]===192.0.2.0/24

1) west 192.1.2.45 pings east-in/east-eth0/east 192.0.2.254 on eastnet 192.0.2.0/24
2) west adds an iptable rule to block plaintext from eastnet
3) west pings 192.0.2.254 again, but pong should be dropped by rule
4) west initiates connection "westnet-eastnet"; east 192.1.2.23 responds
5) netjig sends ping packets from westnet to eastnet
