ZdcConditions: Fix clang warning.

Unused private data member. (Left commented-out because it's still referenced from already commented-out code.)

ForwardDetectors/ZDC/ZdcConditions/ZdcConditions/ZdcCablingService.h

@@ -82,7 +82,7 @@ public:
 
 
     const ZdcID*      m_zdcID;
-    const ZdcHardwareID*    m_zdcHWID;
+    //const ZdcHardwareID*    m_zdcHWID;
 
 
     int m_connected[16][16]{};