'Errback all queued deferreds.'

def _fail(self, error):

    if self._failed:
        return error
    self._failed = 1
    if self.nextDeferred:
        try:
            self.nextDeferred.errback(failure.Failure(ConnectionLost('FTP    connection    lost', error)))
        except defer.AlreadyCalledError:
            pass
    for ftpCommand in self.actionQueue:
        ftpCommand.fail(failure.Failure(ConnectionLost('FTP    connection    lost', error)))
    return error
