Spider memory queue issue

[lorien]

https://ci.appveyor.com/project/lorien/grab/build/1.0.402/job/k39irx29t71ybcub

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FAIL: test_schedule (tests.spider_queue.SpiderMemoryQueueTestCase)
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Traceback (most recent call last):
  File "C:\projects\grab\tests\spider_queue.py", line 83, in test_schedule
    self.assertEqual(bot.stat.collections['numbers'], [1, 3, 4, 2])
AssertionError: Lists differ: [1, 3, 2] != [1, 3, 4, 2]
First differing element 2:
2
4
Second list contains 1 additional elements.
First extra element 3:
2
- [1, 3, 2]
+ [1, 3, 4, 2]
?        +++