Create test certificates before real

[xgin]

Originally reported by @wikrie

create test certificates before creatin real certs https://community.letsencrypt.org/t/testing-against-the-lets-encrypt-staging-environment/6763 or this hint here: Limits on usage Let’s Encrypt will issue a limited number of certificates each week. See this thread for the latest numbers. If you are trying out the client for the first time, you may want to use the --test-cert flag, and a domain name that does not receive live traffic. This will get certificates from our staging server. They won’t be valid in browsers, but otherwise the process will be the same, so you can test a variety of configuration options without hitting the rate limit.