Update node.go

add error info

node/node.go

@@ -294,8 +294,9 @@ func (node *Node) AddPendingTransaction(newTx *types.Transaction) error {
 			node.tryBroadcast(newTx)
 		}
 		return err
+	}else{	
+		return errors.New("shard do not match")
 	}
-	return nil
 }
 
 // AddPendingReceipts adds one receipt message to pending list.