Add data field for A6 record

Since A6 is an obsolete RR type, no DNS part option was created.
This is, however, not consistent with the rest of per-type API
and may cause problems. This patch adds at least a DNS part for
raw A6 record data so that the record type is treated consistently.

This patch also fixes interactive mode for A6 records. Their data
were not detected correctly as dnsrecord_add didn't expect
a number in DNS part option name.

https://fedorahosted.org/freeipa/ticket/2309

ipalib/plugins/dns.py

@@ -466,7 +466,15 @@ class ARecord(DNSRecord):
 class A6Record(DNSRecord):
     rrtype = 'A6'
     rfc = 3226
-    parts = None    # experimental rr type
+    parts = (
+        Str('data',
+            label=_('Record data'),
+        ),
+    )
+
+    def _get_part_values(self, value):
+        # A6 RR type is obsolete and only a raw interface is provided
+        return (value,)
 
 class AAAARecord(DNSRecord):
     rrtype = 'AAAA'
@@ -1639,7 +1647,7 @@ class dnsrecord_add(LDAPCreate):
 
         # check if any record part was added
         for option in options:
-            option_part_re = re.match(r'([a-z]+)_part_', option)
+            option_part_re = re.match(r'([a-z0-9]+)_part_', option)
 
             if option_part_re is not None:
                 record_option = self.obj.get_record_option(option_part_re.group(1))