noderoute: stop gluon-uradvd before reconfiguring network
It seems OpenWRT has a problem when reconfiguring the network with ``/etc/init.d/network reload``: Sometimes when switching from online/server mode (with gluon-uradvd running) to offline/mesh mode (with gluon-uradvd stopped) it seems gluon-uradvd is stopped after IPv6 has been configured to accept RAs. This leads to the router having an IPv6 address inside it's own segment. When the router is reconfigured to online mode (while it has an IPv6 address in it's own segment) it ends up without a IPv6 route into it's own segment (on br-client). (It's not clear if the kernel does not accept the new route or if the route is removed by ``/etc/init.d/network`` (or even something else happens...).) In this mode the router is not able to forward and IPv6 traffic to the clients in it's segent. With this change we make sure that gluon-uradvd is stopped before we reconfigure networking. If needed ``/etc/init.d/network`` will start gluon-uradvd.