We used to shut down peers atomically, but now we flush the
connections there's a delay. If we are asked to connect in that time,
we ignore it, as we are already connected, but that's wrong: we need
to remember that we were told to connect and reconnect.
This should solve a few weird test failures where "connect" would hang
indefinitely.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>