Random bad asserts for stat ops when running tests.
```
======================================================================
FAIL: test_sum (pandas.tests.test_frame.TestDataFrame)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/travis/virtualenv/python2.6_with_system_site_packages/lib/python2.6/site-packages/pandas/tests/test_frame.py", line 10590, in test_sum
    has_numeric_only=True, check_dtype=False, check_less_precise=True)
  File "/home/travis/virtualenv/python2.6_with_system_site_packages/lib/python2.6/site-packages/pandas/tests/test_frame.py", line 10780, in _check_stat_op
    check_less_precise=check_less_precise)  # HACK: win32
  File "/home/travis/virtualenv/python2.6_with_system_site_packages/lib/python2.6/site-packages/pandas/util/testing.py", line 513, in assert_series_equal
    assert_almost_equal(left.values, right.values, check_less_precise)
  File "testing.pyx", line 58, in pandas._testing.assert_almost_equal (pandas/src/testing.c:2554)
  File "testing.pyx", line 93, in pandas._testing.assert_almost_equal (pandas/src/testing.c:1796)
  File "testing.pyx", line 140, in pandas._testing.assert_almost_equal (pandas/src/testing.c:2387)
AssertionError: expected 0.00144 but got 0.00144
```
