Fix ocsp/helper. (#5104)
Fix ocsp/helper. (#5104)

In #5103 I tweaked the help to allow customizing where the output goes,
but I didn't ensure that the output field was always set. Also, I forgot
to expand the `...v` parameter when passing it to Fprintf.
letsencrypt/boulder,bmw/boulder,jcjones/boulder,jcjones/boulder,letsencrypt/boulder,bmw/boulder,letsencrypt/boulder,jcjones/boulder,jsha/boulder,jcjones/boulder,bmw/boulder,jsha/boulder,jsha/boulder