Update to Vagrant v1.5.0

Vagrant v1.5.0 requires Ruby v2.1.1.  Unfortunately, Ruby v2.1 depends on
GMP but the current upstream revision of omnibus-software does not include
GMP, so temporarily point at my fork until they merge my pull request.
Also, switch to using tagged revisions of vagrant-wrapper in order to pull
in the correct version for Ruby v2.1.1.

Signed-off-by: Kent R. Spillner <kspillner@acm.org>