This is mainly just copying over the copy-editing from the
lightning-rfc repository.
[ Split to just perform changes after the UNKNOWN_PAYMENT_HASH change --RR ]
Signed-off-by: Christian Decker <decker.christian@gmail.com>
Reported-by: Rusty Russell <@rustyrussell>
We only take the pubkey and ignore all other fields, so we might as well
save the cycles used computing the hash for something else.
Signed-off-by: Jon Griffiths <jon_p_griffiths@yahoo.com>