[CMake] CPack Windows default CPACK_NSIS_INSTALL_ROOT

[Hugh]

Hi,

I am using CPack to package a 64 bit library using the NSIS CPack 
generator and I am getting the "C:\Program Files (x86)\" as the default 
CPACK_NSIS_INSTALL_ROOT value.  I was expecting to get "C:\Program 
Files\".   Is this the expected behaviour?

Thanks,
Hugh.