Instead of doing this weird chaining, just call them all at once and
use a reference counter.
To make it simpler, we return the subd_req so we can hang a destructor
off it which decrements after the request is complete.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This is a bit different from the other cases: we need to iterate through
the peers and ask all the ones in openingd.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>