local_chan was mainly around so we could "soft" disable channels (and
really disable them once we used the channel_update in an error
message).
Instead we introduce the idea of a "deferred_update": it's either
deferred indefinitely (a peer goes offline, if we need to send it in
an error we'll apply it immediatly), or simply delayed to avoid
spamming everyone.
The resulting rewrite is much clearer, IMHO.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
If there's a rate-card for liquidity, we don't know about it until
after startup (the plugin *should* call us at init to tell us what their
current rates are)
