Opaque pipes are obsolete and should disappear in the future.

Also updates route reload for pipes.

Conflicts:

	proto/ospf/lsreq.c
	proto/ospf/lsupd.c
	proto/ospf/rt.c

And fixes one minor bug.

This can be used to re-feed routes to protocol after soft change in
export filters.

For transparent pipes, loop detection works correctly now.
Pipes are now more symmetric - in both directions filtering
is done in do_rte_announce().

If protocol announces a route, route is accepted by import filter to
routing table, and later it announces replacement of that route that is
rejected by import filter, old route remains in routing table.