COMP: fixed yet more clang warnings, minor stuff

Change-Id: Ica6dedd147152533b7cc8b5f6f9b598ba86f3aee

Common/vtkPolynomialSolversUnivariate.cxx

@@ -2029,7 +2029,7 @@ int vtkPolynomialSolversUnivariate::SolveCubic( double c0, double c1, double c2,
           }
 
         // Reduce Number Of Roots To One 
-        if( (*r1 == *r2) )
+        if( *r1 == *r2 )
           {
           *num_roots = 1;
           }

Graphics/vtkRectilinearGridToTetrahedra.cxx

@@ -540,7 +540,7 @@ int vtkRectilinearGridToTetrahedra::RequestData(
   if (this->TetraPerCell == VTK_VOXEL_TO_5_AND_12_TET)
     {
     vtkDataArray *TempVoxelSubdivisionType = RectGrid->GetCellData()->GetScalars();
-    if((TempVoxelSubdivisionType == NULL))
+    if(TempVoxelSubdivisionType == NULL)
       {
       vtkErrorMacro(<< "Scalars to input Should be set!");
       return 1;

Widgets/vtkProp3DButtonRepresentation.cxx

@@ -137,11 +137,10 @@ GetButtonProp(int i)
 //-------------------------------------------------------------------------
 void vtkProp3DButtonRepresentation::PlaceWidget(double bds[6])
 {
-  int i;
   double bounds[6], center[3], aBds[6], aCenter[3];
 
   this->AdjustBounds(bds, bounds, center);
-  for (i=0; i<6; i++)
+  for (int i=0; i<6; i++)
     {
     this->InitialBounds[i] = bounds[i];
     }

Widgets/vtkTexturedButtonRepresentation.cxx

@@ -206,11 +206,10 @@ PlaceWidget(double scale, double xyz[3], double normal[3])
 //-------------------------------------------------------------------------
 void vtkTexturedButtonRepresentation::PlaceWidget(double bds[6])
 {
-  int i;
   double bounds[6], center[3], aBds[6], aCenter[3];
 
   this->AdjustBounds(bds, bounds, center);
-  for (i=0; i<6; i++)
+  for (int i=0; i<6; i++)
     {
     this->InitialBounds[i] = bounds[i];
     }