[libpanel-applet] Only associate gconf keys with schemas when needed
[libpanel-applet] Only associate gconf keys with schemas when needed

We used to associate the gconf keys with schemas each time an applet
starts. Now, we only do this if the association is needed. This should
make gconf less busy during startup.

This also has the side-effect of working around a recent gconf bug where
panel applets don't use the default values. See bgo#583326.

GNOME/gnome-panel,GNOME/gnome-panel