Avoid displaying unused Binomial counters (!830)

GaudiKernel/GaudiKernel/Counters.h

@@ -813,6 +813,7 @@ namespace Gaudi {
         return printImpl( o, tag );
       }
       virtual MsgStream& print( MsgStream& o, const std::string& tag ) const override { return printImpl( o, tag ); }
+      virtual bool toBePrinted() const override { return this->nEntries() > 0; }
     };
 
     /**