Appending HDF5 store leads to crash
I am appending an HDF5 store with a pandas dataframe and Python crashes without any traceback.

``` python
chunk.to_hdf('all_data.h5', 'df',mode='a',format='table',append=True)
```

Discussion on stackoverflow:

http://stackoverflow.com/questions/31419768/pandas-appending-suing-to-hdf-now-crashes-after-updating-to-pytables-3-2
