SSU2: Don't delete empty ipv6 address at startup

Needed for SSU2 handshakes

router/java/src/net/i2p/router/transport/udp/UDPTransport.java

@@ -3727,7 +3727,10 @@ public class UDPTransport extends TransportImpl implements TimedWeightedPriority
             // which will start up NTCP inbound when we transition to OK.
             if (isIPv6) {
                 if (STATUS_IPV6_FW_2.contains(status)) {
-                    removeExternalAddress(true, true);
+                    if (_enableSSU2)
+                        rebuildExternalAddress(true);   // we must publish i/s/v
+                    else
+                        removeExternalAddress(true, true);
                 } else if (STATUS_IPV6_FW_2.contains(old) &&
                            STATUS_IPV6_OK.contains(status) &&
                            !explicitAddressSpecified()){