Firstly, we need to update the staging fee amount when we queue a change.
Secondly we need to remove completed fee updates, otherwise we hit a
database constraint that peer & state are unique.
Reported-by: Christian Decker
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
I originally overloaded struct htlc for this, as they go through the
same states, but separating them turned out to be clearer.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>