COMP: Suppress Slicer cmake macro warning regarding unquoted if args
COMP: Suppress Slicer cmake macro warning regarding unquoted if args

Policy CMP0054 is not set: Only interpret if() arguments as variables or
  keywords when unquoted.  Run "cmake --help-policy CMP0054" for policy
  details.  Use the cmake_policy command to set the policy and suppress this
  warning.

  Quoted variables like "KIT_TEST_SRCS" will no longer be dereferenced when
  the policy is set to NEW.  Since the policy is not set the OLD behavior
  will be used.
Call Stack (most recent call first):
  SlicerModules/SpatialObjectsModule/Testing/Cxx/CMakeLists.txt:29 (SlicerMacroConfigureGenericCxxModuleTests)

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