Ticket 49722 - Errors log full of " WARN - keys2idl - recieved NULL idl from index_read_ext_allids, treating as empty set" messages
    
    Description:  If searching on entrydn, and the value is not found return an empty
                  list instead of NULL.  This prevent these harmless error messages in
                  log
    
    https://pagure.io/389-ds-base/issue/49722
    
    Reviewed by: ?