Refactor releasenote job to have one path for tox building
Refactor releasenote job to have one path for tox building

The past bash code had two paths for building release notes, it
makes it much harder to refactor and debug (for example, the result
was being moved only if the release notes had translations).

Change-Id: I45272750fc734566d08329d915fbedc10b9eed65

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