Rename "initial" state to "telopt_negotiation"

There was a rare race where if a client disconnected during the
initial Telnet option negotiation pause, an attempt to log an entry
about it would raise an exception because the "initial" state
placeholder in the default menu data was incorrectly-named. Fix
that, and rename the state to "telopt_negotiation" so it's less
confusing to debug if similar issues are discovered with this state
in the future.