Update xtesting to 0.80.0

Update xtesting to 0.80.0

It allows publishing the artifacts via Xtesting.
It's required by the new Xtesting Ansible role [1].

It disables the pylint warning super-on-old-class which is falsy here
(xtesting 0.80 conforms with py3 rules).

[1] https://github.com/collivier/ansible-role-xtesting/commit/8c62525bb0d0b5f8dcc2c4436711d5d075de8811

Change-Id: I832e5e19467c7fd86a46574448faad4d6f2d4c0d
Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
(cherry picked from commit d0ee068c6e1c4a6e0a52156143a04feb6f9a78cb)