Fixing issue where recursive to string method caused crash.

Change-Id: Ia14dff452004da20b15c1c1de890bd348959b171
diff --git a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/DefaultDocumentTreeNode.java b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/DefaultDocumentTreeNode.java
index 2720db8..4b4852b 100644
--- a/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/DefaultDocumentTreeNode.java
+++ b/core/store/primitives/src/main/java/org/onosproject/store/primitives/resources/impl/DefaultDocumentTreeNode.java
@@ -141,7 +141,9 @@
                 .add("key", this.key)
                 .add("value", this.value);
         for (DocumentTreeNode<V> child : children.values()) {
-            helper = helper.add("child", child);
+            helper = helper.add("child", "\n" + child.path().pathElements()
+                    .get(child.path().pathElements().size() - 1) +
+                    " : " + child.value());
         }
         return helper.toString();
     }