Pin tox to 3.14.1 and more_itertools to 7.2.0
Pin tox to 3.14.1 and more_itertools to 7.2.0

This change pins the upstream tox dependency to version 3.14.1
and the more_itertools dependency to version 7.2.0. The latest
versions of these tools released in late November and early
December 2019 have begun to drop support for Python 3.4, breaking
various test builds on Ubuntu 12.04 LTS (at this time the updates
have only made their way into the upstream packages for this OS).
This will likely soon spread to all other Python 3.4 builds, so for
now, short cut the issue by avoiding newer library releases. Once
PyKMIP drops support for Python 3.4, this change can be undone.

OpenKMIP/PyKMIP,OpenKMIP/PyKMIP