p2p: AddrFetch - don't disconnect on self-announcements

Disconnecting an AddrFetch peer only after receiving an addr
message of size >1 prevents dropping them before
they had a chance to answer the getaddr request.

src/net_processing.cpp

@@ -2779,7 +2779,9 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         }
         m_addrman.Add(vAddrOk, pfrom.addr, 2 * 60 * 60);
         if (vAddr.size() < 1000) peer->m_getaddr_sent = false;
-        if (pfrom.IsAddrFetchConn()) {
+
+        // AddrFetch: Require multiple addresses to avoid disconnecting on self-announcements
+        if (pfrom.IsAddrFetchConn() && vAddr.size() > 1) {
             LogPrint(BCLog::NET, "addrfetch connection completed peer=%d; disconnecting\n", pfrom.GetId());
             pfrom.fDisconnect = true;
         }