This removes the reservation cleanup at startup, too, now they're all
using 'reserved_til'.
This changes test_withdraw, since it asserted that outputs were marked
spent as soon as we broadcast a transaction: now they're reserved until
it's mined. Similarly, test_addfunds_from_block assumed we'd see funds
as soon as we broadcast the tx.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: JSON-RPC: `withdraw` now randomizes input and output order, not BIP69.