Added source dependency for external/cordova

I'm not sure how to override the Android versions (the reverse of what's above) or if it can even be done. If I remove the excludes, I think Android picks its own versions anyway. Here's the output:

```
WARNING: Dependency org.apache.httpcomponents:httpclient:4.3.2 is ignored for debug as it may be conflicting with the internal version provided by Android.
         In case of problem, please repackage it with jarjar to change the class packages
```