Allow including SharedArray in other project's dependencies

When SharedArray pulls its version string from Gitlab CI via CI_COMMIT_TAG, this causes an error while pip-installing it as a dependency for another repo in Gitlab CI (version mismatch).

This fix just renames the variable so that it doesn't clash with other repository's CI jobs. I also updated the CI script so that it works given changes to Python 2.

Let me know if I've missed anything. I tested uploading to TestPyPI on another branch to make sure everything works fine: https://test.pypi.org/project/bil-SharedArray-test/