
With the goals of Ussuri being Python 3.6 [1], the python 3.5 environment on Xenial is too old. Remove testing and the most obvious bits of support from devstack. Also drop claimed support for artful, which is long EOL. [1] https://governance.openstack.org/tc/reference/runtimes/ussuri.html Change-Id: Iefcca99904dde76b34efbbfc0e04515dfa5a09e5