Use the "nginx -t" command

[leonardofl]

nginx -t checks the syntax and tests nginx configuration files. I saw about it on https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-16-04.

We can use it on our integration tests.

Or... if any issues appointed by nginx -t prevents nginx to start properly, maybe we can include it on the recipe itself, so it's clearer why nginx did not start well (if the recipe fails, the integration tests will not run).