Using jsonrpc_request_sync, layers are loaded before we finish init,
so we never can be asked to create a layer before we've loaded it
(xpay creates a layer immediately on startup).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-None: persistent layers new this release.
Any file in this directory which is executable and whose name only
consists of alphanumeric characters, space, '.', '-' or '_' will be
automatically loaded when lightningd starts (unless suppressed with
commandline options).