Fix a comment.

  if (rc == 0)

  {

    /*

      Now send the result set metadata to the client. We need to do it

      here, as in Select_materialize::send_fields the exact column types

      are not yet known. The new types may differ from the original ones

      sent at prepare if some of them were altered by MySQL HEAP tables

      mechanism -- used when create_tmp_field_from_item may alter the

      original column type.

      Now send the result set metadata to the client. We need to

      do it here, as in Select_materialize::send_fields the items

      for column types are not yet created (send_fields requires

      a list of items). The new types may differ from the original

      ones sent at prepare if some of them were altered by MySQL

      HEAP tables mechanism -- used when create_tmp_field_from_item

      may alter the original column type.

      We can't simply supply SEND_EOF flag to send_fields, because

      send_fields doesn't flush the network buffer.