Use --publish for openstack-doc-test

This requires openstack-doc-test 0.11: We now can use --publish for
openstack-doc-test. This replaces --nocreate-index.

Change-Id: I5e255326ef35810504467603a98da691e26a332c

tox.ini

@@ -26,4 +26,4 @@ commands = openstack-doc-test --check-build {posargs}
 [testenv:publishdocs]
 # Prepare all documents so that they can get published on
 # docs.openstack.org with just copying publish-docs/* over.
-commands = openstack-doc-test --check-build --nocreate-index --force
+commands = openstack-doc-test --check-build --publish --force