An interop test of Authenticated Header (AH) using sha2_256

This uses IKEv1. It requires netkey

This test requires strongswan 5.1.1 or newer for AH support.

But it requires strongswan < 5.5.2 because there they broke it :/

Seems what we receive is badly formed:

| *****parse ISAKMP Transform Payload (AH):
|    next payload type: ISAKMP_NEXT_NONE (0x0)
|    length: 28 (0x1c)
|    AH transform number: 1 (0x1)
|    AH transform ID: AH_AES_XCBC_MAC (0x9)
| ******parse ISAKMP IPsec DOI attribute:
|    af+type: AUTH_ALGORITHM (0x8005)
|    length/value: 5 (0x5)
|    [5 is AUTH_ALGORITHM_HMAC_SHA2_256]
| ******parse ISAKMP IPsec DOI attribute:
|    af+type: GROUP_DESCRIPTION (0x8003)
|    length/value: 5 (0x5)
|    [5 is OAKLEY_GROUP_MODP1536]


