Set up a simple line of channel pairs, where one should be preferred
over the other for our various reasons. Make sure this works, both
using a low-level call to Dijkstra and at a higher level as the pay
plugin does.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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).