This is one of the last references to `distutils` within `mach`, so let's get rid of it to be thorough. Differential Revision: https://phabricator.services.mozilla.com/D199951
==== mach ==== Mach (German for *do*) is a generic command dispatcher for the command line. To use mach, you install the mach core (a Python package), create an executable *driver* script (named whatever you want), and write mach commands. When the *driver* is executed, mach dispatches to the requested command handler automatically. To learn more, read the docs in ``docs/``.