adding function checkConvergenceControlEq to refactor getWellConvergence

only functional change is that rate control or BHP control has different
tolerance for MSW now.

opm/simulators/wells/StandardWell.hpp

@@ -439,6 +439,10 @@ namespace Opm
                                          Opm::DeferredLogger& deferred_logger) override;
 
         virtual void updateWaterThroughput(const double dt, WellState& well_state) const override;
+
+        void checkConvergenceControlEq(ConvergenceReport& report,
+                                       DeferredLogger& deferred_logger) const;
+
     };
 
 }