Fixed problem with Rakefile downloading Ubuntu Image

curl was unable to download the ubuntu iso.  It seems there was a syntax problem in the rake file.  I removed the syntax problem and curl was able to download the image successfully.  I also changed the default image to 12.04.2.


If interested, here is the error that this fork fixes:
```
rake setup
Running setup task
librarian-puppet install
Download ubuntu install image, this may take a long time
"curl http://releases.ubuntu.com/12.04.2/ubuntu-12.04.2-server-amd64.iso > images/ubuntu-12.04-server-amd64.iso"
sh: 1: curl http://releases.ubuntu.com/12.04.2/ubuntu-12.04.2-server-amd64.iso > images/ubuntu-12.04-server-amd64.iso: not found
rake aborted!
Command failed with status (127): ["curl http://releases.ubuntu.com/12.04.2/u...]
```