random poll fixes delivery problem

test.py

import zmq

context = zmq.Context()
address = "inproc://test"

#subscriber
sub = context.socket(zmq.SUB)
sub.bind(address)
sub.setsockopt(zmq.SUBSCRIBE, "test")
poller = zmq.Poller()
poller.register(sub, zmq.POLLIN)

#publisher
pub = context.socket(zmq.PUB)
pub.connect(address)

# now the messages are delivered -- updating something internally??
poller.poll(100)

#send some messages
pub.send("test 123")
pub.send("test 345")
pub.send("foo 23")
pub.send("test hello")

# retrieve
has_next = True
while has_next:
    has_next = False
    sock = dict(poller.poll(100))
    if sub in sock:
        has_next = True
        msg = sub.recv()
        print msg