Module & Sub module grammar issue fix

Change-Id: Ia90b90510233195c5eab7402ebe790014ce137d1
diff --git a/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java b/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java
index 080767a..14bad1e 100644
--- a/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java
+++ b/src/main/java/org/onosproject/yangutils/parser/impl/listeners/SubModuleListener.java
@@ -82,7 +82,7 @@
         YangSubModule yangSubModule = new YangSubModule();
         yangSubModule.setName(identifier);
 
-        if (ctx.submoduleBody(0).submoduleHeaderStatement().yangVersionStatement() == null) {
+        if (ctx.submoduleBody().submoduleHeaderStatement().yangVersionStatement() == null) {
             yangSubModule.setVersion((byte) 1);
         }