Fix incorrect splitting of Python files into subpackages.
    
    Since the -common subpackage installs files in
    %{python3_sitelib}/%{name}, it should also own that directory instead of
    the main package. Also, exclude files that are in subpackages from the
    main package. Finally, byte-compiled files were not specified correctly
    for Python 3. This was hidden in the main package glob, instead of being
    in the subpackages.