use CM_NULLPTR

Source/CPack/IFW/cmCPackIFWGenerator.cxx

Source/CPack/IFW/cmCPackIFWInstaller.cxx

Source/CPack/IFW/cmCPackIFWPackage.cxx

Source/CPack/IFW/cmCPackIFWRepository.cxx

Source/CPack/cmCPackArchiveGenerator.cxx

Source/CPack/cmCPackComponentGroup.h

Source/CPack/cmCPackDebGenerator.cxx

Source/CPack/cmCPackGenerator.cxx

Source/CPack/cmCPackGenerator.h

Source/CPack/cmCPackGeneratorFactory.cxx

Source/CPack/cmCPackLog.cxx

Source/CPack/cmCPackNSISGenerator.cxx

Source/CPack/cmCPackRPMGenerator.cxx

Source/CPack/cpack.cxx

Source/CTest/cmCTestBZR.cxx

Source/CTest/cmCTestBuildAndTestHandler.cxx

Source/CTest/cmCTestBuildCommand.cxx

Source/CTest/cmCTestBuildHandler.cxx

Source/CTest/cmCTestCVS.cxx

Source/CTest/cmCTestCommand.h