Add oslopolicy script runs to the docs tox target

In an untouched codebase these two commands should not output anything
of interest as they are primarily tools for managing a custom
policy.json file. But it's useful to run them to ensure that they do not
error out.

Change-Id: I33e0b27164a0e9df240337c7e9b467f0f3859eac

tox.ini

@@ -75,6 +75,8 @@ commands =
   bash -c '! find doc/ -type f -name *.json | xargs -t -n1 python -m json.tool 2>&1 > /dev/null | grep -B1 -v ^python'
   oslo-config-generator --config-file=etc/nova/nova-config-generator.conf
   oslopolicy-sample-generator --config-file=etc/nova/nova-policy-generator.conf
+  oslopolicy-list-redundant --namespace nova
+  oslopolicy-policy-generator --namespace nova --output-file etc/nova/policy.yaml.merged
   sphinx-build -W -b html api-guide/source api-guide/build/html
   sphinx-build -W -b html api-ref/source api-ref/build/html