Handle SRV RR target of "." by returning a new error code.

Handle SRV RR target of "." by returning a new error code.
May have memory leaks -- needs checking before pullup.

* locate_kdc.c (struct srv_dns_entry): Move to top level.
(make_srv_query_realm): Separate from krb5_locate_srv_dns_1; just do query and
return results.
(krb5_locate_srv_dns_1): Call it, and build addlist entries.  Check for one RR
with a target of ".", and return an error.
(krb5_locate_srv_dns): Deleted.

ticket: 1549
status: open

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@15560 dc483132-0cff-0310-8789-dd5450dbe970