examples/eldebus: Unregister service interface on shutdown.

As we use this as an example for devlopers we better also handle the
shutdown case cleanly.

src/examples/eldbus/complex-types-server.c

@@ -384,6 +384,7 @@ main(void)
 
    free(resp2);
    ecore_timer_del(timer);
+   eldbus_service_interface_unregister(iface);
    eldbus_connection_unref(conn);
 
    eldbus_shutdown();