Unreliable test test_clipboard:test_round_trip_frame
```
=============================================================================
FAILURE: test_round_trip_frame (pandas.io.tests.test_clipboard.TestClipboard)
-----------------------------------------------------------------------------
Traceback (most recent call last):
  File "c:\Python33-AMD64\Lib\unittest\case.py", line 384, in _executeTestPart
    function()
  File "C:\workspace\pandas_tests\BITS\64\PYTHONVER\33\pandas\io\tests\test_clipboard.py", line 67, in test_round_trip_frame
    self.check_round_trip_frame(dt)
  File "C:\workspace\pandas_tests\BITS\64\PYTHONVER\33\pandas\io\tests\test_clipboard.py", line 55, in check_round_trip_frame
    tm.assert_frame_equal(data, result, check_dtype=False)
  File "C:\workspace\pandas_tests\BITS\64\PYTHONVER\33\pandas\util\testing.py", line 477, in assert_frame_equal
    assert_index_equal(left.columns, right.columns)
  File "C:\workspace\pandas_tests\BITS\64\PYTHONVER\33\pandas\util\testing.py", line 423, in assert_index_equal
    right.dtype))
AssertionError: [index] left [object Index(['TeN9hs1zZI', 'gvGSK2jSbR', 'AvE1VqQppQ'], dtype='object')], right [Index(['Y3XElgd5QX', 'Xp1Xv4NQF2', 'SoKJHMsx3C'], dtype='object') object]
```

Many of the spurious failures on the CI status page come from this test
sporadically failing on windows.

Figure out if it's a real issue or not.
