model: Another set of refactoring/renaming to make code compile (not tested yet)

Refs #1005 (http://redmine.named-data.net/)
diff --git a/model/cs/ndn-content-store.cc b/model/cs/ndn-content-store.cc
index cfe362e..f1c25b7 100644
--- a/model/cs/ndn-content-store.cc
+++ b/model/cs/ndn-content-store.cc
@@ -69,7 +69,7 @@
 const Name&
 Entry::GetName () const
 {
-  return m_header->GetName ();
+  return m_data->GetName ();
 }
 
 Ptr<const ContentObject>