The ChangeLog file is generated when we run `python setup.py sdist`,
which doesn't naturally happen when we run `tox -edocs`, so on a fresh
clone the docs build will fail because it references the ChangeLog file
which isn't there. Since we don't rely on pbr any more for release notes
and we have a sophisticated release note management tool, point the docs
at the published release notes instead of the pbr ChangeLog.
Change-Id: I614091eae739154337795a8f120b68686ad0ed0a
currently there is no release history for keystoneclient, though
sometimes the commits are lacking context, this automated approach
is far better than nothing.
Change-Id: I5a10c32ec21b52ee905cbb1f5c52db807a7b2c5b