Remove a preorder hash.

    DO NOT CALL THIS DIRECTLY.

def namedb_preorder_remove( cur, preorder_hash ):
    """
    Remove a preorder hash.

    DO NOT CALL THIS DIRECTLY.
    """
    try:
        query, values = namedb_delete_prepare( cur, 'preorder_hash', preorder_hash, 'preorders' )
    except Exception, e:
        log.exception(e)
        log.error("FATAL: Failed to delete preorder with hash '%s'" % preorder_hash )
        os.abort()

    log.debug(namedb_format_query(query, values))
    namedb_query_execute( cur, query, values )
    return True