fix: use current node address as default peer list

[VinozzZ]

Which problem is this PR solving?

• Nodes sending peer traffic to localhost (and failing to send peer traffic to localhost) #1369

Short description of the changes

Since GetPeers() in redis peer implementation returns 127.0.0.1:8080 when no peer is present, it causes trace forwarding to fail if all peers have unregistered itself from the system.

• use current node address as the default peer list

[kentquirk]

OK, but the reason that FilePeers returns one peer is that the old trace distribution code expected "peers" to include self, and everything expected at least one peer. And I think that this assumption is still valid for the partitioning code. So why do you ever expect 0 peers?

If we've changed that assumption, we maybe should instead make FilePeers not do that. I'm worried that there's an inconsistency here.