yang choice case translator + whitebox fix

Change-Id: I96f1855bc71a002335946150b51e911ae6ac2fb2
diff --git a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangCase.java b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangCase.java
index 48f5d17..e61d273 100644
--- a/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangCase.java
+++ b/utils/yangutils/src/main/java/org/onosproject/yangutils/datamodel/YangCase.java
@@ -286,7 +286,7 @@
      */
     @Override
     public YangConstructType getYangConstructType() {
-        return YangConstructType.CASE_DATA;
+        return CASE_DATA;
     }
 
     /**
@@ -311,7 +311,7 @@
 
     @Override
     public void detectCollidingChild(String identifierName, YangConstructType dataType) throws DataModelException {
-        if (getParent() == null || !(getParent() instanceof YangChoice)) {
+        if (!(getParent() instanceof YangChoice)) {
             throw new DataModelException("Internal Data Model Tree Error: Invalid/Missing holder in case " +
                     getName());
         }