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

It prints a message to stderr, but actually it's fine with this version:

```
dump-gossipstore: UNKNOWN GOSSIP minor VERSION 14 (expected 12)
```

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

And fix up gossip_store backwards comment!

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

We want to be able to clear them, and fetch them.

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

…ing.

This avoids us gossiping about nodes which don't have live channels.

Interstingly, we previously tested that we *did* gossip such node
announcements, and now we fix that test.

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

…channel!

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

We can update dying channels, though it seems weird!  We accept gossip about them,
we just don't propagate it.

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

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

We accept node_announcements on dying channels, but make sure we
set the dying flag it channels are alll dying.

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

…l_announcements.

We make sure a node_announcement is preceeded by at least one channel_announcement,
but dying ones don't count (as they are not broadcast!).

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

…move last channel.

Normally, channels are marked dying, the 12 blocks later, removed.
But for local channels, we can access any spliced channel already, so
we remove them immediately from our local gossip.  This left a hole in
our logic, if that channel was the last one keeping a
node_announcement alive.

Solution is to unify with the "moved node_announcement" path.

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

…yet.

This happens if:
1. The peer sets a timestamp filter to non-zero, and
2. We have a channel_announcement without a channel_update.

The timestamp is 0 as a placeholder as part of the recent gossip rework
(we used to hold these channel_announcement in memory, which was complex).

But this means we won't send it in this case, and if we later send the
channel_update, CI will complain about 'Bad gossip order'.

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