It looked like we weren't printing the address on closing outputs.
But we are, because the 'scriptPubkey' field is in the 'outputs' db
table since 0.7.3 (66a47d2761).
So make the logic clearer, and remove a completely bogus comment (UTXOs
with closing_info are definitely spendable!).
We export the json_add_utxos() for future use, too.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
1708fb91e5