When pip-installing any of these packages, pip hit our permissive, any-version "setuptools" dependency first and then ignored all subsequent, more constrained ones, like cryptography's "setuptools>=1.0". See https://github.com/pypa/pip/issues/988. It thus, on a box with setuptools 0.9.8, stuck with that version. Then, at runtime, letsencrypt crashed because pkg_resources couldn't satisfy cryptography's setuptools>=1.0 requirement.

This change lets us pip-install our packages and have it work. We'll need to make sure our direct requirements (all of them) satisfy the more constrained requirements of our dependencies. Yes, it is disgusting.