Some minor updates including fixing issues with the HTML5 output
generated by Sphinx 2.0, inlining the OpenStack logo rather than
referencing it from elsewhere, and adding a new SOURCE_DATE_EPOCH option
for use in reproducible builds.
Change-Id: Ie6743fa52434abf8ba0f0aa4db741552e6ccfb95
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>