Added data to test a big upgrade

This adds the following data:
* the export of an install of the packages as reported by Amir on https://github.com/ocaml/opam/issues/985 (github omd mpp core lwt ctypes utop cow mirari tuntap async yojson core_extended core_bench cohttp async_graphics cryptokit menhir), with the repo as of 2013-12-01
* a current tar-gz of the packages/ dir of the repo

Using those it will be easy to replay the upgrade scenario. Currently, it's instant with aspcud, and I could'nt have it succeed with the internal heuristic.

Remains to add an automatic test of this in the tests.