Zaqar has already dropped py34[1], so the text "py34" and
"Runs the Python unit tests with a Python 3.4 environment."
need to be deleted. Besides, we should support py35.
[1]https://review.openstack.org/#/c/418170/
Change-Id: Id5aa108160582b71a792d58b793c7b1da1096305
Closes-Bug: #1686038