Basic pluto test, except the policy has been adjusted to permit only
cast128 for for phase 2. This uses NETKEY, not KLIPS as KLIPS does not
support cast128.

However, it seems NETKEY does not support cast128 either:

"westnet-eastnet-cast128" #2: ERROR: netlink response for Add SA esp.fe470ce2@192.1.2.45 included errno 38: Function not implemented

