COMP: Fix duplicate inherited member issues.

Fix duplicate inherited member warnings in
vtkBiDimensionalRepresentation2D reported at:
https://open.cdash.org/viewBuildError.php?type=1&buildid=4730716

Interaction/Widgets/vtkBiDimensionalRepresentation2D.h

@@ -148,18 +148,6 @@ protected:
   vtkTextMapper   *TextMapper;
   vtkActor2D      *TextActor;
 
-  // Internal variables
-  double P1World[3];
-  double P2World[3];
-  double P3World[3];
-  double P4World[3];
-  double P21World[3];
-  double P43World[3];
-  double T21;
-  double T43;
-  double CenterWorld[3];
-  double StartEventPositionWorld[4];
-
   // Helper method
   void ProjectOrthogonalPoint(double x[4], double y[3], double x1[3], double x2[3], double x21[3],
                               double dir, double xP[3]);