Fix broken links

As noted in [1] oslo.config has a few broken links, this should fix the ones seen
in the oslo.config repo:

* Glossary has moved, use new URL
* Update config-reference to current URL.

[1]
http://lists.openstack.org/pipermail/openstack-docs/2017-January/009464.html

Change-Id: I922454c7791d4fb8e3834884462ce7311b223bd2