Omnibus Updates

* Update to Omnibus 1.3.0
* Update Omnibus cookbook to 1.2.2
* Simplify Vagrant-based build lab …
  * Combine all platforms into a single Vagrantfile.
  * Update Vagrantfile to Omnibus 1.3.0 format.


This change was successfully tested against all platforms in CI:
http://ci.opscode.us/job/chef-client-build/1193/

/cc @sersut @lamont-granquist @danielsdeleo