Bug 967216 - Intermittent calendar/test/unit/app_test.js | app global events moztimechange | expected 2 to equal 1

We change the `_mozTimeRefreshTimeout` as `1`(ms), so I think the race condition might be happened. How do you think? I think we should not change the `_mozTimeRefreshTimeout`. It also change the logic of the listener[1].

[1] https://github.com/mozilla-b2g/gaia/blob/master/apps/calendar/js/app.js#L540-L547