COMP: Undefine Py_hash_t when wrapping VtkGlue
COMP: Undefine Py_hash_t when wrapping VtkGlue

Both VTK and SWIG >= 3.0.11 contain Python 2 compatibility definitions
of Py_hash_t. VTK uses a typedef while SWIG uses a preprocessor
definition. Undefine the proprocessor definition to avoid build errors
for VTKGlue.

Addresses:

  /ITK-build/Wrapping/Modules/ITKVtkGlue/itkImageToVTKImageFilterPython.cpp:980:19: error: declaration does not declare anything [-fpermissive]
 #define Py_hash_t long
                   ^
 /VTK/Wrapping/PythonCore/vtkPythonCompatibility.h:81:14: note: in expansion of macro 'Py_hash_t'
 typedef long Py_hash_t;

ITK-3532

Change-Id: Iad79f1c1a7b6ede6dd71695705565ae0567a8d5f

hjmjohnson/ITK,vfonov/ITK,thewtex/ITK,vfonov/ITK,stnava/ITK,LucasGandel/ITK,fbudin69500/ITK,fbudin69500/ITK,hjmjohnson/ITK,hjmjohnson/ITK,hjmjohnson/ITK,blowekamp/ITK,richardbeare/ITK,Kitware/ITK,spinicist/ITK,malaterre/ITK,blowekamp/ITK,stnava/ITK,spinicist/ITK,PlutoniumHeart/ITK,malaterre/ITK,fbudin69500/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,richardbeare/ITK,BRAINSia/ITK,Kitware/ITK,Kitware/ITK,PlutoniumHeart/ITK,richardbeare/ITK,BRAINSia/ITK,Kitware/ITK,stnava/ITK,LucasGandel/ITK,blowekamp/ITK,hjmjohnson/ITK,spinicist/ITK,fbudin69500/ITK,vfonov/ITK,vfonov/ITK,PlutoniumHeart/ITK,vfonov/ITK,malaterre/ITK,vfonov/ITK,LucasGandel/ITK,blowekamp/ITK,fbudin69500/ITK,thewtex/ITK,thewtex/ITK,blowekamp/ITK,BRAINSia/ITK,malaterre/ITK,blowekamp/ITK,stnava/ITK,BRAINSia/ITK,LucasGandel/ITK,Kitware/ITK,thewtex/ITK,stnava/ITK,PlutoniumHeart/ITK,LucasGandel/ITK,vfonov/ITK,blowekamp/ITK,PlutoniumHeart/ITK,thewtex/ITK,spinicist/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,malaterre/ITK,InsightSoftwareConsortium/ITK,thewtex/ITK,PlutoniumHeart/ITK,PlutoniumHeart/ITK,vfonov/ITK,stnava/ITK,blowekamp/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,malaterre/ITK,richardbeare/ITK,richardbeare/ITK,PlutoniumHeart/ITK,spinicist/ITK,hjmjohnson/ITK,spinicist/ITK,malaterre/ITK,spinicist/ITK,stnava/ITK,stnava/ITK,fbudin69500/ITK,hjmjohnson/ITK,Kitware/ITK,vfonov/ITK,spinicist/ITK,LucasGandel/ITK,malaterre/ITK,Kitware/ITK,LucasGandel/ITK,malaterre/ITK,spinicist/ITK,LucasGandel/ITK,fbudin69500/ITK,richardbeare/ITK,stnava/ITK,fbudin69500/ITK,BRAINSia/ITK,thewtex/ITK