UPDATE generates wrong key_values

[Marcus Eriksson]

The transaction log generated by this sequence of commands generates bad key values in the transaction log for the update:
---
drizzle> create table test1 (id int not null primary key, test varchar(10));
Query OK, 0 rows affected (0.04 sec)

drizzle> insert into test1 values(1,"one"),(2,"two");
Query OK, 2 rows affected (0 sec)
Records: 2 Duplicates: 0 Warnings: 0

drizzle> update test1 set test="updated" where id=2;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1 Changed: 1 Warnings: 0
---
the update generates the following statement in the log:

---
type: UPDATE
start_timestamp: 1258919032892967
end_timestamp: 1258919032893773
update_header {
  table_metadata {
    schema_name: "unittests"
    table_name: "test1"
  }
  key_field_metadata {
    type: INTEGER
    name: "id"
  }
  set_field_metadata {
    type: VARCHAR
    name: "test"
  }
}
update_data {
  segment_id: 1
  end_segment: true
  record {
    key_value: "2"
    key_value: "updated"
    after_value: "updated"
  }
}
---
The key_values in the update data record should only contain "2"