eth, p2p: start the p2p server even if maxpeers == 0

eth/backend.go

@@ -449,14 +449,10 @@ func (s *Ethereum) Start() error {
 		ClientString:    s.net.Name,
 		ProtocolVersion: ProtocolVersion,
 	})
-
-	if s.net.MaxPeers > 0 {
-		err := s.net.Start()
-		if err != nil {
-			return err
-		}
+	err := s.net.Start()
+	if err != nil {
+		return err
 	}
-
 	// periodically flush databases
 	go s.syncDatabases()