[COOK-4530] Enable new options in gunicorn config for secure headers from proxy and proc name

https://tickets.opscode.com/browse/COOK-4530

* secure_scheme_headers
* forwarded_allow_ips
* proc_name

Reference

* http://docs.gunicorn.org/en/latest/settings.html#process-naming
* http://docs.gunicorn.org/en/latest/settings.html#secure-scheme-headers
* http://docs.gunicorn.org/en/latest/settings.html#forwarded-allow-ips