FindPythonLibs Fixes, master branch (2019.10.09.)
Made FindPythonLibs.cmake
work correctly with the Gaudi build. I forgot about setting some variables previously, which Gaudi desperately depends on for its build.
This is a follow-up from the previous Python3 compatibility updates discussed in ATLINFR-3221. (This is the type of issue that I was suspicious about with our build issues seen last Friday in that ticket.)