[imp] Improve the default view in com_joomlaupdate

### Tracker:
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=33830&start=0

### How to test

1. Install 3.3.0
2. switch update server to testing
3. See the update message on com_joomlaupdate
4. choose FTP (and enter a test PW)
5. see old_updater.jpg
6. apply patch (e.g. with Patchtester)
7. see the message again
8. see that the FTP Password imput is hidden
9. see: new_updater.jpg

#### Old updater view
![old_updater](https://cloud.githubusercontent.com/assets/2596554/3211205/708f29ee-ef09-11e3-9579-2e6a8aa099bf.JPG)
#### New updater view
![new_updater](https://cloud.githubusercontent.com/assets/2596554/3211206/70989b00-ef09-11e3-81a0-87a36f78bf6e.JPG)