irkerd: Close a Dispatcher after a bad-password error

irkerd: Close a Dispatcher after a bad-password error

Instead of continually trying to reconnect.  If the server didn't like
your password last time, it's not likely to like it next time either.
Bad-password errors aren't covered in RFC 2812 (the ERROR entry is
very general [1]).  Charybdis seems to use:

  ERROR :Closing Link: webirc. (Bad Password)

and ngIRCd uses:

  ERROR :Access denied: Bad password?

[1]: http://tools.ietf.org/html/rfc2812#section-3.7.4