COMP: Fix different CMake if/endif for TubeTK_USE_BOOST.
COMP: Fix different CMake if/endif for TubeTK_USE_BOOST.

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