We don't want to re-create them internally, ever.
The test-cli tools are patched to generate them all the time, but
they're not performance critical.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Hand anchor details and pubkeys directly; this is what we want
for the actual daemon which doesn't keep raw packets around.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>