On first visit in firefox, must-staple certs (unlike chrome which ignores must-staple) always fail.
Investigating, it turns out, nginx does not fetch OCSP responses on reload or restart - https://trac.nginx.org/nginx/ticket/812 .
So, one has to prime the OCSP cache using curl requests. Alternately, one can use `openssl ocsp -noverify -no_nonce` and
then set `ssl_stapling_file`. Both approaches won't work if the OCSP servers are down and then we have to have some retry logic.
Also, the cache is per nginx worker, so I have no clue how many times one has to call curl. The `ssl_stapling_file` approach
requires some refresh logic as well. All very messy.
For the moment, do not set must-staple in the cert. Instead, check if the cert has a CSP URL and then enable
stapling in nginx accordingly.
Girish Ramakrishnan
7a7223a261