automatically update puppet modules when running vagrant

[mgrauer]

When spinning up a vm with vagrant, it would be nice for the librarian-puppet to run at that time, updating all of the puppet module dependencies.

There is a way to run a script provision in vagrant, but this runs on the guest machine, and I think I'd like this to run in the host machine.

At the current time the way around this is to run the librarian-puppet update once before a vm is spun up with vagrant.