fix(system): fix tree node

src/main/java/com/elephant/framework/galaxy/aroad/module/system/dto/TreeNode.java

@@ -13,7 +13,7 @@ import java.util.List;
 public class TreeNode {
 	protected int id;
 	protected int parentId;
-	protected List<TreeNode> children = new ArrayList<TreeNode>();
+	protected List<TreeNode> children;
 
 	public void add(TreeNode node) {
 		children.add(node);