VRMLImporter: Fix crash. Avoid dereferencing NULL pointer (#1624)
VRMLImporter: Fix crash. Avoid dereferencing NULL pointer (#1624)

Bug fixed by using code similar to the "diff" attached to the bug
report. Thanks to Steve Robbins for the diff.

The two wrl files in the bug report now work, and the bridge.wrl file
from the VTK wiki example for the VRMLImporter also works. All without
reporting memory leaks.

Change-Id: Ia4ba461155237ad3edd2075c93fb31c61bb48d75

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