The easiest way to do this is to play with the 'wallet_tx' semantics
and have 'amount' have meaning even when 'all_funds' is set.
Note that we change the string 'Cannot afford funding transaction' to
'Cannot afford transaction' as this code is also used for withdrawls.
Inspired-by: molz on #c-lightning
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
No new functionality, just a continuation of my work toward completing #665.
I removed the common members of `struct withdrawal` and `struct fund_channel`
and placed them in a new `struct wallet_tx`. Then it was fairly straightforward
to reimplement the existing code in terms of `wallet_tx`.
Since I made some structural changes I wanted to get this approved before I
go any farther.
Added 'all' to fundchannel help message.