Bug fix for --nat-rand-port mode to ensure that the port to be
NAT'd is properly defined so that the fwknopd server will NAT
connnections to this port instead of applying the NAT operation to the
port that is to be accessed via -A. This change also prints the
randomly assigned port to stdout regardless of whether --verbose mode is
used (since it not then the user will have no idea which port is
actually going to be NAT'd on the fwknopd side).
This is a fairly significant commit that lays the groundwork for getting
selectable HMAC modes working for both the client and server. One libfko API
change was required so that the hmac_type is passed into fko_new_with_data().
This allows the server to set the hmac_type via access.conf stanzas. The
effort in this commit will be extended to allow HMAC MD5, SHA1, and SHA512
also function properly.