Reparent tox-py35-on-zuul to zuul-tox-py35
Reparent tox-py35-on-zuul to zuul-tox-py35

With the recent changes in zuul-web zuul has a customized tox-py35
job. We need to use that as parent.

Change-Id: If5370497121b20332d67a61563e4597c623dcc15

openstack-infra/openstack-zuul-jobs,openstack-infra/openstack-zuul-jobs