Prevent null dereferences
Prevent null dereferences

Change-Id: I34437c615cddf42cae3f2f4e0431847679a0c251

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