Now we're always sync, just use an fd. Put the hsm_sync_read() helper
here, too, and do HSM init sync which makes things much simpler.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Splitting the detection for outputs that we own into a separate
`wallet_extract_owned_outputs` function and use it when the broadcast
succeeds to re-add the change output back to the database.
Christian Decker
Rusty Russell