Add "nocommitwait" for the two cases we test that, otherwise add
assertions that we never end up dealing with anything other than
the previous commit.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
We simply record how many fee changes there are, rather than supporting
a particular level.
Fees are tricky: it's a noop to apply them when incoming, but we apply them
when they've been acked. Unlike HTLC modifications, which are symmetric,
fee updates only apply when returning to the originating node.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>