Debian wheezy test failure: test_pytables.py:test_encoding  'f' != 'foo'
```
======================================================================
FAIL: test_encoding (pandas.io.tests.test_pytables.TestHDFStore)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/tmp/buildd/pandas-0.13.0/debian/tmp/usr/lib/python2.7/dist-packages/pandas/io/tests/test_pytables.py", line 856, in test_encoding
    tm.assert_frame_equal(store['df'], df)
  File "/tmp/buildd/pandas-0.13.0/debian/tmp/usr/lib/python2.7/dist-packages/pandas/util/testing.py", line 498, in assert_frame_equal
    check_less_precise=check_less_precise)
  File "/tmp/buildd/pandas-0.13.0/debian/tmp/usr/lib/python2.7/dist-packages/pandas/util/testing.py", line 447, 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:2561)
  File "testing.pyx", line 93, in pandas._testing.assert_almost_equal (pandas/src/testing.c:1803)
  File "testing.pyx", line 69, in pandas._testing.assert_almost_equal (pandas/src/testing.c:1499)
AssertionError: 'f' != 'foo'
```

pytables 2.3.1-3
