[cc][localres] forward to implementation for flux calculation

Overloading the evalFlux function for a single scvf did not have
any effect as we did not forward the call to the implementation

dumux/assembly/cclocalresidual.hh

@@ -65,7 +65,7 @@ public:
     {
         const auto& scv = fvGeometry.scv(scvf.insideScvIdx());
         const auto localScvIdx = scv.indexInElement();
-        residual[localScvIdx] += evalFlux(problem, element, fvGeometry, elemVolVars, elemFluxVarsCache, scvf);
+        residual[localScvIdx] += this->asImp().evalFlux(problem, element, fvGeometry, elemVolVars, elemFluxVarsCache, scvf);
     }
 
     //! evaluate the flux residual for a sub control volume face