Change the way to evaluate DELETE request

- Add withhistory to recover the creator
- Remove the check of the user creator test for now, I need
  to figure out how to detect who is the maintainer in the
  tgt_project
- Check that the package is not needed in the tgt_project
  (usually Factory)
Accept the DELETE request sooner if it is safe. Otherwise add a comment
Detect if the author of a delete request iis the maintainer of tgt_project
Merge pull request #267 from aplanas/master

Change the way to evaluate DELETE request