Both keywords are used with dns-01 and dns-persist-01 challenges to pass
information to an external DNS provisioning tool (e.g. the dataplaneAPI)
via the "dpapi" sink. provider-name sets the DNS provider identifier and
acme-vars passes arbitrary tool-specific variables.
Thanks to @oliwer for reporting the issue.
Must be backported to 3.2, however previous version don't have
"dns-persist-01".