StoreGate: Suppress cppcheck warning.

Suppress a cppcheck warning about a member intentionally not copied in operator=.

Control/StoreGate/StoreGate/WriteHandle.icc

 /*
-  Copyright (C) 2002-2019 CERN for the benefit of the ATLAS collaboration
+  Copyright (C) 2002-2023 CERN for the benefit of the ATLAS collaboration
 */
 
 // $Id: WriteHandle.icc 797637 2017-02-17 02:32:11Z ssnyder $
@@ -119,7 +119,10 @@ WriteHandle<T>::WriteHandle(WriteHandle&& h)
  */
 template <class T>
 inline
-WriteHandle<T>& 
+WriteHandle<T>&
+// m_lockAuxPending not copied --- want lifetime to stay with the
+//  original WH.
+// cppcheck-suppress operatorEqVarError
 WriteHandle<T>::operator= (const WriteHandle& h)
 {
   if (this != &h)