test_random.test_sample_prob_from_scores occasionally fails

[fritzo]

======================================================================
FAIL: distributions.tests.test_random.test_sample_prob_from_scores
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.7_with_system_site_packages/local/lib/python2.7/site-packages/nose/case.py", line 197, in runTest
    self.test(*self.arg)
  File "/home/travis/build/forcedotcom/distributions/distributions/tests/test_random.py", line 210, in test_sample_prob_from_scores
    assert_samples_match_scores(sampler)
  File "/home/travis/build/forcedotcom/distributions/distributions/tests/util.py", line 217, in assert_samples_match_scores
    assert_counts_match_probs(counts, probs)
  File "/home/travis/build/forcedotcom/distributions/distributions/tests/util.py", line 203, in assert_counts_match_probs
    assert gof > tol, 'failed with goodness of fit {}'.format(gof)
AssertionError: failed with goodness of fit 0.000945166953359
--------------------  begin captured stdout ---------------------
EXPECT  ACTUAL  VALUE
10000.0 10000   0
goodness of fit = 1
EXPECT  ACTUAL  VALUE
5693.5  5747    0
4306.5  4253    1
goodness of fit = 0.126409842659
EXPECT  ACTUAL  VALUE
5779.1  5802    2
2534.8  2458    0
1686.1  1740    1
goodness of fit = 0.0671215589621
EXPECT  ACTUAL  VALUE
8314.4  8298    2
670.7   706 0
585.9   581 1
429.0   415 3
goodness of fit = 0.44019109939
EXPECT  ACTUAL  VALUE
4839.9  4842    3
1876.9  1901    2
1808.5  1814    1
1412.0  1379    0
62.6    64  4
goodness of fit = 0.856219051563
EXPECT  ACTUAL  VALUE
3088.0  3109    4
2174.6  2212    3
1713.8  1651    2
1430.5  1450    5
808.0   794 1
785.0   784 0
goodness of fit = 0.495742040274
EXPECT  ACTUAL  VALUE
2266.4  2226    0
2015.0  2095    5
1752.0  1722    2
1525.7  1621    3
904.2   846 4
872.3   807 6
664.4   683 1
goodness of fit = 0.000945166953359
---------------------  end captured stdout  ----------------------
----------------------------------------------------------------------
Ran 310 tests in 28.206s
FAILED (SKIP=10, failures=1)
make: *** [test_cy] Error 1
The command "make test$FLAVOR" exited with 2.
Done. Your build exited with 1.