Fix Build is failing on TravisCI

In December 2013 vagrant switched to use ruby 2.0.0 for their builds
and test. As we require vagrant to build and test we need to bump the
versions. See https://github.com/mitchellh/vagrant/commit/88bb0a3.
Merge pull request #28 from klarna/fix-build-on-travisci

Fix Build is failing on TravisCI