This change is really to allow us to have a --dev-fail-on-subdaemon-fail option
so we can handle failures from subdaemons generically.
It also neatens handling so we can have an explicit callback for "peer
did something wrong" (which matters if we want to close the channel in
that case).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Use a negative timestamp as the flag for this, making the test simple.
This allows valgrind to detect that we're accessing them prematurely,
including across the wire on gossip_getchannels_entry.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
