deprecated attribute: `dns.record.rr_chain_target_subnet_list`, `dns.fqdn.rr_chain_target_subnet_list`
ab v4.1:
die attribute dns.record.rr_chain_target_subnet_list, dns.fqdn.rr_chain_target_subnet_list werden durch jeweils rr_chain_target_subnet_gfk_list ersetzt.
weitere subnetz-attribute (cidr, ...) muessen ueber die api-constraints api_func_dns_fqdn_rr_chain_target_contains_subnet, api_func_dns_record_rr_chain_target_contains_subnet geholt werden.