Fixed gate by Updating Gemfile to pin Rake to 10.1.1

The latest Rake update requires Ruby >= 1.9. Bundler in the
current gate uses 1.8.x. This update fixes the gate by pinning
Rake to the last known working version.

Change-Id: I649b58086bd6b3fb01e1717b07f0b0d36040222e
Merge git://github.com/puppetlabs/puppetlabs-nova