add an autostart condition: gnome-shell comes with its own
implementation of a policy kit agent, however the fallback session does
not and needs polkit-gnome-authentication-agent to be started.
This only affects the !gtk2 FLAVOR (polkit-gnome,gtk2 will automatically
start as usual).
Revert the upstream commit that removed the autostart file for now,
because desktop sessions have not yet have time to deal with it.
Explicitely use gtk+2.
ok jasper@
PolicyKit-gnome provides a GTK+/GNOME frontend for PolicyKit.
Despites its name, this package is not GNOME specific, it can be used by
other Gtk+2 Desktops.