Rapid Concurrent Access Breaks HDFStore
There are several errors associated with this. One of them is that the HDFStore fails to load some tables inside the store file, but fails silently. Another error is a loud HDF5 error that gives a full traceback. Both should be visible in the following code.

```
import pandas as pd
import multiprocessing as mp

def f(x):
    tt = pd.HDFStore('storage.h5', mode = 'r')
    print tt

p = mp.Pool()
p.map(f, range(50))
```
