power-icon: use org.gnome.SessionManager.Presence
power-icon: use org.gnome.SessionManager.Presence

use org.gnome.SessionManager.Presence to get "session idle"
notifications.

Fixes: BMC#330

meego-netbook-ux/meego-panel-devices,meego-netbook-ux/meego-panel-devices,meego-netbook-ux/meego-panel-devices