drop using statement for wsalt

rather qualify member function calls with this->

opm/simulators/wells/StandardWell.hpp

@@ -262,7 +262,6 @@ namespace Opm
 
     protected:
         // protected functions from the Base class
-        using Base::wsalt;
         using Base::wsolvent;
         using Base::wpolymer;
         using Base::wfoam;

opm/simulators/wells/StandardWell_impl.hpp

@@ -682,7 +682,7 @@ namespace Opm
             const unsigned waterCompIdx = Indices::canonicalToActiveComponentIndex(FluidSystem::waterCompIdx);
             EvalWell cq_s_sm = cq_s[waterCompIdx];
             if (this->isInjector()) {
-                cq_s_sm *= wsalt();
+                cq_s_sm *= this->wsalt();
             } else {
                 cq_s_sm *= this->extendEval(intQuants.fluidState().saltConcentration());
             }