* Set ssl_stapling_verify to off per https://sslmate.com/blog/post/ocsp_stapling_in_apache_and_nginx ('on' has no security benefits).
* Set resolver to 127.0.0.1, instead of Google Public DNS, because we might as well use our local nameserver anyway.
* Remove the commented line which per the link above would never be necessary anyway.

OCSP seems to work just fine after these changes.