Comment 4 for bug 724205

I've created another patch that avoids introducing a new variable by making sure that the the log-in button is disabled if MODE_AUTHENTICATION is used and no queries are pending.
This debdiff is against gdm-2.30.5-0ubuntu4 (maverick), the main difference to the version proposed upstream is that the ubuntu code has a reset_dialog call in gdm_greeter_login_window_ready, which makes the set_{sensitive,focus,ready} calls in this method superflous.
I've tested this patch with timed login, password less login with user list, password less login without user list, login with password with user list, login with password without user list.