Minor improvement: Added ordering to bootstrap classes

I really like the idea, that the bootstrap is installing librarian-puppet and is doing the fetching of the modules. I implemented the same in our setup.
One thing a stumbled upon was the ordering of the bootstrap classes. I got the problem, that the git package was installed after the 'librarian install' command. This caused with librarian-puppet to fetch the git resources. In the current code, it works out of the box just fine. But this is IMHO due to luck. ;-)

This patch will enforce a correct ordering of the bootstrap classes.

I also removed the dependency to puppet and factor. They are preinstalled in the debain vagrant box of puppetlabs. If you remove them and start the provisioning, the problem described above will occur. The ordering just worked with the package requirement of 'puppet' and 'factor'. Ordering is sometime a big pain in Puppet. ;-(