fixes configparser in python 2.x

configparser is a module that has the constructor function so calling `configparser` before resulted in a `TypeError: 'module' object is not callable` error.

BTW, I was unable to run the tests to verify that this didn't break anything. I tried to follow the `HACKING.txt` instructions but ran into this:
```
$ python --version
Python 2.7.8
$ python bootstrap.py
Traceback (most recent call last):
  File "bootstrap.py", line 105, in <module>
    ws.find(pkg_resources.Requirement.parse(requirement)).location
AttributeError: 'NoneType' object has no attribute 'location'
```

Simply running `nosetest` I get `ERROR: Failure: NameError (name 'get_ipython' is not defined)`.