Merge branch 'gcc9.AthContainersInterfaces-20181211' into 'master'

AthContainersInterfaces: Fix gcc9 warnings.

See merge request atlas/athena!16678

Former-commit-id: 9c31d874

Control/AthContainersInterfaces/AthContainersInterfaces/IAuxSetOption.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
+  Copyright (C) 2002-2018 CERN for the benefit of the ATLAS collaboration
 */
 
 // $Id$
@@ -36,7 +36,7 @@ class IAuxSetOption
 {
 public:
   /// Make sure this class has a vtable.
-  virtual ~IAuxSetOption() {}
+  virtual ~IAuxSetOption() = default;
 
 
   /**

Control/AthContainersInterfaces/AthContainersInterfaces/IAuxTypeVector.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
+  Copyright (C) 2002-2018 CERN for the benefit of the ATLAS collaboration
 */
 
 // $Id: IAuxTypeVector.h 793692 2017-01-24 16:27:09Z ssnyder $
@@ -41,7 +41,7 @@ class IAuxTypeVector
 {
 public:
   /// Destructor.
-  virtual ~IAuxTypeVector() {}
+  virtual ~IAuxTypeVector() = default;
 
 
   /**

Control/AthContainersInterfaces/AthContainersInterfaces/IConstAuxStore.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
+  Copyright (C) 2002-2018 CERN for the benefit of the ATLAS collaboration
 */
 
 // $Id: IConstAuxStore.h 612954 2014-08-21 19:25:01Z ssnyder $
@@ -64,7 +64,7 @@ class IConstAuxStore
 {
 public:
   /// Destructor.
-  virtual ~IConstAuxStore() {}
+  virtual ~IConstAuxStore() = default;
 
 
   /**