Remove distro.make

[dkingofpa]

The distro.make file should be located with the site's profile. If you add or remove modules from the make file, chances are you also want to enable or remove the dependency in the profile.info as well. Currently, it's a nuisance to make a module change and have to commit those changes to two different repos (site repo, profile repo).

We can just keep the example.make file here and provide strong suggestions to also download the xforty-drupal profile. Documentation would need updated as well.