test_take_ownership_via_controller fails in Tor's Travis CI

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FAIL: test_take_ownership_via_controller

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Traceback (most recent call last):

  File "/home/travis/build/torproject/tor/stem/stem/util/test_tools.py", line 152, in <lambda>

    self.method = lambda test: self.result(test)  # method that can be mixed into TestCases

  File "/home/travis/build/torproject/tor/stem/stem/util/test_tools.py", line 225, in result

    test.fail(self._result.msg)

AssertionError: tor didn't quit after the controller that owned it disconnected

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Ran 22 tests in 13.394s

FAILED (failures=1)

https://travis-ci.org/torproject/tor/jobs/627483530#L3621

This is the first time I've seen this failure. Maybe the timeout is too low?