HeartbeatTest.test_heartbeat_stopped test failure

[olukas]

master (commit 4e017c5)

Test tests.heartbeat_test.HeartbeatTest.test_heartbeat_stopped fails on Windows: https://hazelcast-l337.ci.cloudbees.com/view/Official%20Builds/job/python-client-windows/32/testReport/tests.heartbeat_test/HeartbeatTest/test_heartbeat_stopped/

Stacktrace:

Traceback (most recent call last):
  File "C:\Python27\lib\unittest\case.py", line 329, in run
    testMethod()
  File "C:\Jenkins\workspace\python-client-windows\tests\heartbeat_test.py", line 77, in test_heartbeat_stopped
    self.assertTrueEventually(assert_heartbeat_stopped_and_restored)
  File "C:\Jenkins\workspace\python-client-windows\tests\base.py", line 60, in assertTrueEventually
    assertion()
  File "C:\Jenkins\workspace\python-client-windows\tests\heartbeat_test.py", line 70, in assert_heartbeat_stopped_and_restored
    self.assertEqual(1, len(stopped_collector.connections))
  File "C:\Python27\lib\unittest\case.py", line 513, in assertEqual
    assertion_func(first, second, msg=msg)
  File "C:\Python27\lib\unittest\case.py", line 506, in _baseAssertEqual
    raise self.failureException(msg)
AssertionError: 1 != 0