btcd: return nil instead of err when newServer() is interrupted

Author: allocz

btcd.go

@@ -269,6 +269,9 @@ func btcdMain(serverChan chan<- *server) error {
 		// TODO: this logging could do with some beautifying.
 		btcdLog.Errorf("Unable to start server on %v: %v",
 			cfg.Listeners, err)
+		if err.Error() == "interrupt requested" {
+			return nil
+		}
 		return err
 	}
 	defer func() {