Suricata

The function KRB5State.parse function requires a couple of improvements in code readability:

- Giving meaningful names to the kerberos message types, probably the MessageType struct defined in krb5_constants.rs could be used for this

- Rename the KRB5State.req_id to KRB5State.req_type, since it is used to track the request type (AS-REQ, TGS-REQ, etc), not an unique id per request, and its name is misleading