gossipd: don't try to connect to non-routable addresses.

Someone could try to announce an internal address, and we might probe
it.

This breaks tests, so we add '--dev-allow-localhost' for our tests, so
we don't eliminate that one.  Of course, now we need to skip some more
tests in non-developer mode.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

lightningd/lightningd.c

@@ -51,6 +51,7 @@ static struct lightningd *new_lightningd(const tal_t *ctx)
 	ld->dev_debug_subdaemon = NULL;
 	ld->dev_disconnect_fd = -1;
 	ld->dev_subdaemon_fail = false;
+	ld->dev_allow_localhost = false;
 
 	if (getenv("LIGHTNINGD_DEV_MEMLEAK"))
 		memleak_init(ld, backtrace_state);