g-s-d and SM

[jacob berkman <jacob ximian com>]

as reported in bug #85030, if g-s-d gets lost from the session, and
activated by one of the capplets, it won't register with the session
manager, so won't be started on login next time.

at this point, the user can't even manually start g-s-d to add it to
their session, since there's already one running.

a couple of options:

        1.  add something to tell g-s-d the SM
        2.  have gnome-session start g-s-d via bonobo-activation and
        remove it from the session
        3.  punt it, since this shouldn't be happening
        4.  something else?

g-s-d not running causes tons of "bugs" to the user, and i fear this
will be a common problem with gnome 2.

 - jacob