Bug : HDFStore is still locked after closing the file
#### Code Sample, a copy-pastable example if possible
After running this code : 
```
store.append(tablename, df_i, format=format, complib=complib)
store.close(); del store
```
#### Problem description
I cannot delete/move the windows h5 store file, it is still locked by Python.exe


#### Expected Output
We expect the file being release.

#### Output of ``pd.show_versions()``
pandas: 0.18.1

<details>
pandas: 0.18.1

</details>
