[Swan-dev] switching to longer IKEv2 names in logs

[Andrew Cagney]

For instance, when describing integrity, log:

    hmac_sha2_256_96

instead of:

    SHA2_256 or SHA2_256-128 or ...

(no the 96 isn't a typo, see trunkbug :-)

The rationale is two fold:

- IKEv1 assumes (see nat_traversal.c) that all IKE (phase 1) PRFs are
implemented using a MAC (hash) and the HMAC construct and so referring
to the MAC is hopefully sufficient; in IKEv2 that is not true.
  Instead IKEv2 uses longer, less ambiguous names (for instance,
aes_cmac{,_96}, and hmac_sha2_256{,_96,_128}) and we should be using
those.

- Internally, pluto still has entrenched assumptions that all
algorithms have an IKEv1 number/name.  Specifically, for the case in
hand, generic code uses:
    enum_short_name(&oakley_hash_names, ike_info->ike_halg)
  or
    enum_short_name(&oakley_hash_names, ike_info->ike_prf->ikev1_oakley_id)
  to print algorithm names.
  Instead it should use ike_info->ike_prf->common.name

Unfortunately, common.name is a mess so making this change means both
cleaning up common.name and changing log output.

Andrew