This tells the plugin both the `lightning-dir` as well as the
`rpc-filename` to use to talk to `lightningd`. Prior to this they'd
had to guess.
Signed-off-by: Christian Decker <decker.christian@gmail.com>
Also includes some sanity checks for the results returned by the
plugin, such as ensuring that the ID is as expected and that we have
either an error or a real result.
Christian Decker
Rusty Russell