Docs: Fix doc building under CI

Under CI the CouchDB version configured can break the LaTeX PDF
building.

This patch munges the release name for doc builds.

Python styles from Eli Stevens and Alexander Shorin.

Closes COUCHDB-2007
Merge branch '2007-fix-docs-under-ci'

* 2007-fix-docs-under-ci:
  Docs: Fix doc building under CI