Fix old ticket #9092 where a playbook can enter in recursion

This can be tested with this command :

    ansible -c local -m copy -a 'src=/etc/group dest=foo/' all

This is a corner case of the algorithm used to find how we should
copy recursively a folder, and this commit detect it and avoid it.

Check https://github.com/ansible/ansible/issues/9092 for the story