devel/py-oslotest: Update to 4.4.1

• Remove Python 2.7 support that was dropped with the 4.0.0 release.

• Also remove the DOCS option as the documentation contains mostly references to external sites and isn't really useful for offline use.

• Make port concurrent safe as some scripts are installed outside of the Python sitelib directory.

Changelog since 3.2.0:

https://docs.openstack.org/releasenotes/oslotest/ussuri.html