Use twine to upload python package to pypi.

* modules/jenkins/files/slave_scripts/pypi-extract-metadata.py: Twine
deals with metadata for us, this script is no longer needed.

* modules/jenkins/files/slave_scripts/pypi-upload.sh: Use twine instead
of calculating md5sum ourselves and extracting metadata then uploading
with curl.

* modules/openstack_project/manifests/pypi_slave.pp: Insteall twine
(replaces pkginfo dependency).

* modules/openstack_project/templates/pypirc.erb: Twine can use a pypirc
to determine where and with what credentials to upload pacakges.
Create a .pypirc for twine.

Change-Id: I8a6aaf5d2c77151a60c2c660e1ff8570fc9255ea
Merge "Use twine to upload python package to pypi."