These are not needed for unit tests and we want to avoid conflicts when
running with older python versions that we still test against.

We intentionally duplicate ansible and reno as requirements in order to
avoid having to install more items than necessary.

Signed-off-by: Dr. Jens Harbott <harbott@osism.tech>
Change-Id: I0ec83c3e4ae38f911b922a3bade65429d91169eb