Add accidentally deleated return type to regHist

GaudiKernel/GaudiKernel/ITHistSvc.h

@@ -42,7 +42,7 @@ public:
   virtual StatusCode regHist( const std::string& name, std::unique_ptr<TH1> hist, TH1* hist_ptr ) = 0;
   /// @deprecated {Just for compatibility purposes. Ownership should be clearly managed.}
   /// Register an existing ROOT histogram TH*X with name and pointer
-  regHist( const std::string& name, TH1* ) = 0;
+  virtual StatusCode regHist( const std::string& name, TH1* ) = 0;
   /// Return histogram with given name as TH1*, THistSvcMT still owns object.
   virtual StatusCode getHist( const std::string& name, TH1*&, size_t index = 0 ) const = 0;
   /// Return histogram with given name as TH2*, THistSvcMT still owns object.