Add option to control the shutdown confirmation/countdown for Karmic

With the new indicator app in Karmic, they removed the preferences dialog (at least so far as of A6). So, you can't change the option to not have it give the confirmation and countdown for shutdown, stand-by, and reset. There is a gconf option to turn them off. In Jaunty, you could easily select it via a preferences dialog. It might be good to add a "Startup" option for configuring this key.

GConf key: /apps/indicator-session/suppress_logout_restart_shutdown