Specific twine repository when publishing packages

* modules/jenkins/files/slave_scripts/pypi-upload.sh: Specify pypi as
the repository when uploading python packages to pypi. Not doing this
results in a key error when twine attempts to look up the repository.

Change-Id: I7e3c6398710e9b69d1c4576a1e2417e4ca156b97
Merge "Specific twine repository when publishing packages"