Set some of the new config values and enable openstackdocstheme as an
extension so it will inject values into the page context as it writes
each documentation page. This ensures the pages link to the right bug
tracker, etc.
Change-Id: I36d400358b1b5e2c2423c43f43c775bafb0d4721
Depends-On: Icf3a40ed104cfd828f532f6f2b112ed02f996ff5
Signed-off-by: Doug Hellmann <doug@doughellmann.com>