BUG: PDF Segmenter overwritten by RidgeSeedFilter.Update()
BUG: PDF Segmenter overwritten by RidgeSeedFilter.Update()

This commit fixes #665. After reading the discriminant information,
the PDF Segmenter was overwritten in the Update() function of
itktubeRidgeSeedFilter.hxx.

aylward/ITKTubeTK,KitwareMedical/ITKTubeTK,KitwareMedical/TubeTK,cdeepakroy/TubeTK,cdeepakroy/TubeTK,aylward/ITKTubeTK,sumedhasingla/TubeTK,thewtex/TubeTK,KitwareMedical/TubeTK,thewtex/TubeTK,sumedhasingla/TubeTK,sumedhasingla/TubeTK,thewtex/TubeTK,KitwareMedical/TubeTK,KitwareMedical/ITKTubeTK,cdeepakroy/TubeTK,KitwareMedical/ITKTubeTK,cdeepakroy/TubeTK,KitwareMedical/TubeTK,thewtex/TubeTK,sumedhasingla/TubeTK,KitwareMedical/ITKTubeTK,aylward/ITKTubeTK,aylward/ITKTubeTK