Fix OCW origin server's fluentD access log parsing (#933)
Fix OCW origin server's fluentD access log parsing (#933)

Fix OCW origin server's access log format in Nginx configuration so
that fluentD can parse it correctly. Include the `nginx` pillar in top.sls
under 'roles:ocw-origin' so that the `nginx.ng` state knows the
correct log format parameters.

mitodl/salt-ops,mitodl/salt-ops