Remove some now unused forwarding headers.h (DataModel-00-23-72)

	* Tagging DataModel-00-23-72.
	* Remove unused forwarding headers: Arena.h, ClassName.h,
	OwnershipPolicy.h, unordered_map.h, tools/ArenaPoolSTLAllocator.h,
	tools/DVLInfo.h.


Former-commit-id: 5afc6c00

Control/DataModel/DataModel/Arena.h

-// This file's extension implies that it's C, but it's really -*- C++ -*-.
-
-/*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
-*/
-
-// $Id: Arena.h 559676 2013-08-28 18:44:37Z ssnyder $
-// Moved to AthAllocators.
-
-#ifndef DATAMODEL_ARENA_H
-#define DATAMODEL_ARENA_H
-
-
-#include "AthAllocators/Arena.h"
-
-
-#endif // not DATAMODEL_ARENA_H

Control/DataModel/DataModel/ClassName.h

-// This file's extension implies that it's C, but it's really -*- C++ -*-.
-
-/*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
-*/
-
-// $Id: ClassName.h 559821 2013-08-29 20:51:26Z ssnyder $
-
-/**
- * @file  DataModel/ClassName.h
- * @author scott snyder
- * @date Jul 2005
- * @brief An interface for getting the name of a class as a string.
- */
-
-
-#ifndef DATAMODEL_CLASSNAME_H
-#define DATAMODEL_CLASSNAME_H
-
-// moved to SGTools for dependency issues
-#include "SGTools/ClassName.h"
-
-#endif // not DATAMODEL_CLASSNAME_H

Control/DataModel/DataModel/OwnershipPolicy.h

-/*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
-*/
-
-#ifndef DATAMODEL_OWNERSHIPPOLICY_H
-# define DATAMODEL_OWNERSHIPPOLICY_H
-
-#include "AthContainers/OwnershipPolicy.h"
-
-#endif // DATAMODEL_OWNERSHIPPOLICY_H

Control/DataModel/DataModel/tools/ArenaPoolSTLAllocator.h

-// This file's extension implies that it's C, but it's really -*- C++ -*-.
-
-/*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
-*/
-
-// $Id: ArenaPoolSTLAllocator.h,v 1.2 2008-08-26 02:12:26 ssnyder Exp $
-// Moved to AthAllocators
-
-#ifndef DATAMODEL_ARENAPOOLSTLALLOCATOR
-#define DATAMODEL_ARENAPOOLSTLALLOCATOR
-
-
-#include "AthAllocators/ArenaPoolSTLAllocator.h"
-
-
-#endif // DATAMODEL_ARENAPOOLSTLALLOCATOR

Control/DataModel/DataModel/tools/DVLInfo.h

-// This file's extension implies that it's C, but it's really -*- C++ -*-.
-
-/*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
-*/
-
-// $Id: DVLInfo.h,v 1.2 2008-06-17 00:44:17 ssnyder Exp $
-// Moved to AthContainers.
-
-#ifndef DATAMODEL_DVLINFO_H
-#define DATAMODEL_DVLINFO_H
-
-
-#include "AthContainers/tools/DVLInfo.h"
-
-
-#endif // not DATAMODEL_DVLINFO_H

Control/DataModel/DataModel/unordered_map.h

-// This file's extension implies that it's C, but it's really -*- C++ -*-.
-
-/*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
-*/
-
-// $Id: unordered_map.h,v 1.4 2008-01-03 21:20:51 ssnyder Exp $
-/**
- * @file DataModel/unordered_map.h
- * @author scott snyder <snyder@bnl.gov>, copied from gcc4.
- * @date Apr, 2007
- * @brief This is the TR1 unordered_set implementation from gcc4,
- *        adapted to build in Atlas.  Once the TR1 library is available
- *        on all our platforms, we can switch to using the system-supplied
- *        version instead.
- *
- * This has been moved to CxxUtils, leaving this as a forwarding header
- * for now.
- */
-
-#ifndef DATAMODEL_UNORDERED_MAP_H
-#define DATAMODEL_UNORDERED_MAP_H
-
-#include "CxxUtils/unordered_map.h"
-
-#endif /* GNU_LIBSTDCXX_TR1_UNORDERED_MAP_ */