The docstring of getExtensions service in cinder.service.js
was a copy from nova service and not correct. The docstring was
updated based on the current cinder v2 API.
Thanks to a recent improvement in reno, touching release notes
in older releases in the master branch no longer polute the rendered
release notes. Changing URLs (or other things) in the master branch
does not affect the rendered release notes, but updating URLs to the
latest would help avoiding mechanical patches of updating links :)
Change-Id: I2aec3adeb400323d42a3a5083f8bc0798eeff917