Silence unused argument warning.

opm/simulators/utils/ParallelSerialization.cpp

@@ -46,7 +46,7 @@ void eclStateBroadcast(Parallel::Communication comm, EclipseState& eclState, Sch
                        SummaryConfig& summaryConfig,
                        UDQState& udqState,
                        Action::State& actionState,
-                       WellTestState& wtestState)
+                       WellTestState& /* wtestState */)
 {
     Opm::EclMpiSerializer ser(comm);
     ser.broadcast(eclState);