A few fix of hidl-gen for vts generator.

* Remove component_type.
* Use the new VectorDataValueMessage.

Bug: 30762234
Change-Id: I4262240c1b79129bc3801eba3b6037843a484220
diff --git a/Interface.cpp b/Interface.cpp
index 33e8c88..f8647a5 100644
--- a/Interface.cpp
+++ b/Interface.cpp
@@ -220,7 +220,8 @@
     out << "type: TYPE_HIDL_CALLBACK\n"
         << "predefined_type: \""
         << localName()
-        << "\"\n";
+        << "\"\n"
+        << "is_callback: true\n";
     return OK;
 }