Update __init__.py

fixes #842 on my Raspberry PI. 
Are you sure this is the reason the issue went away?

As far as I can see from https://docs.python.org/2/library/warnings.html#warnings.filterwarnings you're using the `filterwarnings()` function wrong, and are actually providing the optional `category` argument to `filterwarnings()` instead of adding a second filter, which would require a new call to `warnings.filterwarnings('ignore', ...)`.

Also, I'd use the the full text to make it more obvious what's being ignored, e.g.: 

``` python
warnings.filterwarnings('ignore', 'Cannot autolaunch D-Bus without X11 $DISPLAY')
```