* Several gardening tasks for Python
1. Update pipenv to 2018.7.1, which is the most recent release that
isn't broken on Python 2
2. Update our pylint dependency to 1.9, the most recently released
version
3. Re-enable pylint for the Pulumi package
* Back out of pipenv upgrade
It's apparently broken in our CI. Also upgrade pylint to 2.1, which is
apparently the "actual" most recently release according to PyPI.
* Fix a bad merge
