add requirement for python-neutronclient

This change enables side-by-side code updates as we transition to
Neutron across integrated projects.

Change-Id: Ib86e068aa8e4f48993809b6b25444407b7c1f17e
Add oslo.sphinx

Allow projects to use the new oslo.sphinx version of the OpenStack
doc theme instead of copying it into each repo.

blueprint oslo.sphinx

Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>
Change-Id: I0bd91f7bb43f97b99051fed65b75fc05d5149cc8