YANG sub module linking + unsupported yang construct + defect fix

Change-Id: I224c8c14ee2111f6844278cb540c48651544f59b
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/DefaultListener.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/DefaultListener.java
index fc9b84a..a4511bc 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/DefaultListener.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/parser/impl/listeners/DefaultListener.java
@@ -39,6 +39,8 @@
  * defaultStatement : DEFAULT_KEYWORD string STMTEND;
  */
 
+import org.onosproject.yangutils.datamodel.YangChoice;
+import org.onosproject.yangutils.datamodel.YangLeaf;
 import org.onosproject.yangutils.datamodel.YangTypeDef;
 import org.onosproject.yangutils.parser.Parsable;
 import org.onosproject.yangutils.parser.antlrgencode.GeneratedYangParser;
@@ -83,6 +85,16 @@
                 typeDef.setDefaultValueInString(ctx.string().getText());
                 break;
             }
+            case LEAF_DATA: {
+                YangLeaf leaf = (YangLeaf) tmpNode;
+                leaf.setDefaultValueInString(ctx.string().getText());
+                break;
+            }
+            case CHOICE_DATA: {
+                YangChoice choice = (YangChoice) tmpNode;
+                choice.setDefaultValueInString(ctx.string().getText());
+                break;
+            }
             default:
                 throw new ParserException(constructListenerErrorMessage(INVALID_HOLDER,
                         DEFAULT_DATA, ctx.string().getText(), ENTRY));