These were missed for some reason. Let's add them now.
While we're here, we add the '-d DOCTREE_DIR' argument to our
'sphinx-build' call to handle Sphinx 1.8's change in behavior for where
doctrees are output.
Change-Id: I5c862a74f92a44bf5248f858e26826eef76c11f0
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>