TileTrackingGeometry: Fix clang warnings.

Unused private data member.

TileCalorimeter/TileTrackingGeometry/TileTrackingGeometry/TileVolumeBuilder.h

 /*
-  Copyright (C) 2002-2017 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2020 CERN for the benefit of the ATLAS collaboration
 */
 
 ///////////////////////////////////////////////////////////////////
@@ -72,7 +72,6 @@ namespace Tile {
 
       const TileDetDescrManager*                        m_tileMgr;                        //!< Calo DetDescrMgr
       std::string                                       m_tileMgrLocation;                //!< Location of the CaloDetDescrMgr
-      const CaloDetDescrManager*                        m_calo_dd;
        
       ToolHandle<Trk::ITrackingVolumeHelper>            m_trackingVolumeHelper;           //!< Helper Tool to create TrackingVolumes
       ToolHandle<Trk::ITrackingVolumeCreator>           m_trackingVolumeCreator;          //!< Second helper for volume creation

TileCalorimeter/TileTrackingGeometry/src/TileVolumeBuilder.cxx

@@ -62,7 +62,6 @@ Tile::TileVolumeBuilder::TileVolumeBuilder(const std::string& t, const std::stri
   AthAlgTool(t,n,p),
   m_tileMgr(0),
   m_tileMgrLocation("Tile"),
-  m_calo_dd(0),
   m_trackingVolumeHelper("Trk::TrackingVolumeHelper/TrackingVolumeHelper"),
   m_trackingVolumeCreator("Trk::CylinderVolumeCreator/TrackingVolumeCreator"),
   m_tileBarrelEnvelope(25.*mm),