validate baloo_file.desktop

Fix per,
$ desktop-file-validate /etc/xdg/autostart/baloo_file.desktop --warn-kde
/etc/xdg/autostart/baloo_file.desktop: warning: value "Service" for key "Type" in group "Desktop Entry" is a reserved value for KDE
/etc/xdg/autostart/baloo_file.desktop: error: key "Exec" is present in group "Desktop Entry", but the type is "Service" while this key is only valid for type "Application"

other DE's complain about this on login otherwise (e.g. gnome)