misc: updated chosen module

## Ready State: (Yes)

This Pull Request updates the chosen module in the drush make file from 2.0-beta2 to 2.0-beta4. This changes the path from where it downloads the library in the chosen drush make file. 

## Requirements & Dependencies


## Deployment Instructions

* Merge code.
* The the chosen.make file in the chosen module has been removed between alpha2 and alpha4, so the chosen library download has been added to our drush make file.
* If you're only updating chosen and not running the entire installkit, you can re-download chosen and run drush make on the chosen.make.example file.
`drush make profiles/imagex_installkit/drupal-org.make ./ --no-core --contrib-destination=profiles/imagex_installkit --working-copy --no-gitinfofile --projects=chosen`  
followed by:  
`drush make profiles/imagex_installkit/modules/contrib/chosen/chosen.make.example ./ --no-core --contrib-destination=profiles/imagex_installkit --working-copy --no-gitinfofile`
* Clear caches with `drush cache-clear all`

## Usage/Test Instructions

* Make sure the chosen library works on the defined elements. In my case it also prevented the Panels relationship dialog to render, so that might be worth testing as well.