BUG #5094: bad result in dblink_get_result when async command sending

The following bug has been logged online:

Bug reference: 5094
Logged by: Sergey Tomoulevitch
Email address: phoinix(dot)public(at)gmail(dot)com
PostgreSQL version: 8.4
Operating system: any
Description: bad result in dblink_get_result when async command
sending
Details:

Good day!

I find one bug in your function dblink_get_result.
When I send command in async query, eq:

SELECT dblink_send_query('remoteconn', 'INSERT INTO mytable (f1, f2) VALUES
(1,2);');

I can not get result for this, eq:

SELECT dblink_get_result('remoteconn');

I got error "ERRCODE_DATATYPE_MISMATCH".
May be...

if (PQnfields(res) != tupdesc->natts)...

is so bad, because PQnfields(res) - is empty for command?