Python: stop ignoring empty string arguments in CLIs
This was needed because of quoting issues when GUB produced Windows installers with NSIS. It is no longer relevant. See commit a49f2bc1 and https://github.com/gperciva/gub/pull/3
This was needed because of quoting issues when GUB produced Windows installers with NSIS. It is no longer relevant. See commit a49f2bc1 and https://github.com/gperciva/gub/pull/3