Sketcher: Solver Interface - Treat length equality parameter as a dri…

…ven parameter to enable redundant constraint reporting

src/Mod/Sketcher/App/Sketch.cpp

@@ -2256,7 +2256,9 @@ int Sketch::addEqualConstraint(int geoId1, int geoId2)
         double dy2 = (*l2.p2.y - *l2.p1.y);
         double value = (sqrt(dx1*dx1+dy1*dy1)+sqrt(dx2*dx2+dy2*dy2))/2;
         // add the parameter for the common length (this is added to Parameters, not FixParameters)
-        Parameters.push_back(new double(value));
+        double *drivenvalue = new double(value);
+        Parameters.push_back(drivenvalue);
+        DrivenParameters.push_back(drivenvalue);
         double *length = Parameters[Parameters.size()-1];
         int tag = ++ConstraintsCounter;
         GCSsys.addConstraintEqualLength(l1, l2, length, tag);