Call the producer.close() in a while loop will case an Error

[CheongHoo]

my code is like this:

while True:
    producer = KafkaProducer(bootstrap_servers=KAFKA_SERVER)
    producer.send('test', b'xxx')
    producer.close()

it will cause a error like bellow:
error: [Errono 9] Bad file descriptor
point to the line
if self._wake_w.send(b'x') !=1 in the client_async.py

[ryanjmccall]

addressed in the latest release 1.3.4 cf #1069