CMake: Do not generate build directories with spaces in them

When a project is first time configured, the kit selection for targets "Release with Debug Information" and "Minimum Size Release" will generate "/<path>/build-<proj>Desktop-Release with Debug Information" and "/<path>/build<proj>Desktop-Minimum Size Release"

In some cases the presence of the spaces will generate configuration problems and since Qt Creator runs CMake twice it will appear very suspicious to have one successful run and one failed run.

Please use - instead of spaces in the directory name.