dnsforwardzone-add: support dnspython 2.0
The command dnsforwardzone-add is assuming that the dns.rrset.RRset
type stores "items" as a list. With dnspython 2.0 this is not true
as a dict is used instead.
As a consequence, in order to get the first record, it is not possible
to use items[0]. As dict and list are both iterables, next(iter(items))
can be used in order to be compatible with dnspython 1.16 and 2.0.
Fixes: https://pagure.io/freeipa/issue/8481
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>