This allows tincctl to receive log messages from a running tincd,
independent of what is logged to syslog or to file. Tincctl can receive
debug messages with an arbitrary level.
If we don't have ECDSA keys for the node we connect to, set protocol_minor
to 1, to indicate this to the other end. This will first complete the
old way of authentication with RSA keys, and will then exchange ECDSA keys.
The connection will be terminated right afterwards, and the next attempt
will use ECDSA keys.
