Add ipaDNSVersion option to dnsconfig* commands and use new attribute
Ad-hoc LDAP calls in DNS upgrade code were hard to maintain and
ipaConfigString was bad idea from the very beginning as it was hard to
manipulate the number in it.
To avoid problems in future we are introducing new ipaDNSVersion
attribute which is used on cn=dns instead of ipaConfigString.
Original value of ipaConfigString is kept in the tree for now
so older upgraders see it and do not execute the upgrade procedure again.
The attribute can be changed only by installer/upgrade so it is not
exposed in dnsconfig_mod API.
Command dnsconfig_show displays it only if --all option was used.
https://fedorahosted.org/freeipa/ticket/5710
Reviewed-By: Martin Basti <mbasti@redhat.com>