Raring LSB Codename Hack

Cloudera only has repository structure for Precise (12.04 LTS) and
Lucid. Cookbook fails to install repo on anything but these two, this
hack checks for raring (13.04) and directs to the Precise (12.04) CDH
repo.
Fix conditional = vs. ==
Merge pull request #48 from 24601/master

Add "support" for Ubuntu 13.04 (raring lsb codename)