[CMake] CPack preinstall

[KSpam]

> Is there a way to disable running the preinstall target while running
> CPack?
>
> Unfortunately, the preinstall target takes a significant amount of time
> (very large project), and it gets run for each component when selecting
> specific components for packaging.  In the case of my very large project
> containing several dozen potential components, a single CPack script might
> bundle a dozen components into an installer.  This would require running
> preinstall a dozen times.  The overhead is simply unbearable.

To avoid running the preinstall command, use CPACK_INSTALL_COMMANDS instead of 
CPACK_INSTALL_CMAKE_PROJECTS.