An aggressive mode test where east emulates an old Cisco that only
allows MODP1024 and MODP1536. West uses an ike= line without modp
group so it gets the default list that contains MODP2048.

In libreswan-3.10 it caused the connection to fail. In libreswan-3.11,
the for IKEv1 with multiple modp groups it wil prefer DH 2 or DH 5.
