random25863.example.org appears in multiple port 80 virtualhosts in the
nginx testdata tarball and also is in the nginx-roundtrip-testdata.
Certbot doesn't handle these properly, which results in random test
failures.
This commit ensures that random25863.example.org only appears in a
single virtualhost and should ensure that the tests pass consistently.
* rewrite nginx parser to allow everything that nginx does
* also make changes in tls_sni_01.py
* add test case with
* allow embedded variables
* allow empty ${} variable
* fix quotes
* un-special case if
* update all tests to reflect current parsing
* escape in QuotedString after merge
* add test cases for variable weirdness that are almost certainly nginx bugs
* update regex for correct variable rules
* close paren doesn't invoke last_space
* Make test file valid Nginx syntax
