Fix warning in vtkOpenGLScalarsToColorsPainter
Fix warning in vtkOpenGLScalarsToColorsPainter

This fixes a "forcing conversion to bool" warning in the
vtkOpenGLScalarsToColorsPainter::RenderInternal() method.

Change-Id: I736aee9819062bf283e3bac15ffab96dfdb958d3

sumedhasingla/VTK,sankhesh/VTK,demarle/VTK,demarle/VTK,biddisco/VTK,sumedhasingla/VTK,keithroe/vtkoptix,ashray/VTK-EVM,jmerkow/VTK,SimVascular/VTK,biddisco/VTK,keithroe/vtkoptix,demarle/VTK,hendradarwin/VTK,mspark93/VTK,johnkit/vtk-dev,keithroe/vtkoptix,ashray/VTK-EVM,ashray/VTK-EVM,johnkit/vtk-dev,jmerkow/VTK,msmolens/VTK,biddisco/VTK,SimVascular/VTK,sankhesh/VTK,SimVascular/VTK,msmolens/VTK,ashray/VTK-EVM,sankhesh/VTK,hendradarwin/VTK,jmerkow/VTK,collects/VTK,demarle/VTK,candy7393/VTK,jmerkow/VTK,msmolens/VTK,hendradarwin/VTK,biddisco/VTK,keithroe/vtkoptix,msmolens/VTK,sankhesh/VTK,candy7393/VTK,msmolens/VTK,keithroe/vtkoptix,gram526/VTK,johnkit/vtk-dev,biddisco/VTK,sankhesh/VTK,biddisco/VTK,hendradarwin/VTK,mspark93/VTK,candy7393/VTK,johnkit/vtk-dev,berendkleinhaneveld/VTK,sankhesh/VTK,berendkleinhaneveld/VTK,sumedhasingla/VTK,candy7393/VTK,collects/VTK,mspark93/VTK,hendradarwin/VTK,collects/VTK,keithroe/vtkoptix,demarle/VTK,SimVascular/VTK,berendkleinhaneveld/VTK,candy7393/VTK,ashray/VTK-EVM,ashray/VTK-EVM,jmerkow/VTK,sumedhasingla/VTK,jmerkow/VTK,sumedhasingla/VTK,SimVascular/VTK,gram526/VTK,jmerkow/VTK,demarle/VTK,mspark93/VTK,berendkleinhaneveld/VTK,gram526/VTK,sumedhasingla/VTK,ashray/VTK-EVM,sankhesh/VTK,mspark93/VTK,ashray/VTK-EVM,biddisco/VTK,mspark93/VTK,gram526/VTK,msmolens/VTK,hendradarwin/VTK,candy7393/VTK,candy7393/VTK,demarle/VTK,sumedhasingla/VTK,gram526/VTK,mspark93/VTK,collects/VTK,collects/VTK,jmerkow/VTK,johnkit/vtk-dev,demarle/VTK,SimVascular/VTK,gram526/VTK,berendkleinhaneveld/VTK,sankhesh/VTK,collects/VTK,candy7393/VTK,mspark93/VTK,SimVascular/VTK,johnkit/vtk-dev,sumedhasingla/VTK,gram526/VTK,SimVascular/VTK,gram526/VTK,hendradarwin/VTK,msmolens/VTK,berendkleinhaneveld/VTK,msmolens/VTK,keithroe/vtkoptix,keithroe/vtkoptix,johnkit/vtk-dev,berendkleinhaneveld/VTK