argument to the CLIENT_USERAUTH_FAILURE method.
(client_userauth_state): Added attribute next.
(userauth_method_is_useful): New function.
(do_userauth_failure): Don't modify current. Instead, increment
next as appropriate, and pass the new again argument to
CLIENT_USERAUTH_FAILURE
(do_exc_client_userauth): Update current correctly, unsing the new
next attribute.
(exc_userauth_disconnect): New class.
(make_exc_userauth_disconnect): New function.
(do_client_userauth): Use make_exc_userauth_disconnect().
(send_password): Simplified tried_empty_passwd handling; just
increment it.
(do_password_failure): Use again and tried_empty_passwd to figure
out what to do.

* src/client_userauth.c (exc_client_userauth): Renamed (was
client_exc_userauth). Updated all uses.

* src/client_userauth.c: Added trace output.

Rev: src/client_userauth.c:1.38