The ACME v2 implementation uses separate directoies for ECC and on-ECC certificates. The renew command for a domain checks if an ECC directory exists (having a "_ecc" suffix) and refuses the command unless the "--ecc" flag was specified. Confusingly, this flag is only required to *renew* an ECC certificate, but not to issue it. This fixes https://github.com/Froxlor/Froxlor/issues/820.