AAPT2: Fix references to private parent

Change-Id: Id4697551b6c8cb6167f562de593006ae3c6158c0
diff --git a/tools/aapt2/ResourceValues.cpp b/tools/aapt2/ResourceValues.cpp
index 04c375f..be963ff 100644
--- a/tools/aapt2/ResourceValues.cpp
+++ b/tools/aapt2/ResourceValues.cpp
@@ -457,6 +457,9 @@
 void Style::print(std::ostream* out) const {
     *out << "(style) ";
     if (parent && parent.value().name) {
+        if (parent.value().privateReference) {
+            *out << "*";
+        }
         *out << parent.value().name.value();
     }
     *out << " ["