We select the close key index at opening time, but the non-DF code didn't correctly register the
address as possibly used for P2WPKH for older nodes.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Fixed: wallet: we could miss our own returned outputs on mutual closes if peer doesn't support option_shutdown_anysegwit (you will still need to rescan after update, if this happened to you!)
Reported-by: Grubles