Revert "Merge pull request #631 from metaflow/fix-delete-key-as-directory"

This reverts commit b87972713e17fb815bfe42f25a63f94f232007e2, reversing
changes made to bd8d45ce28d6f9ddb9c5164f58aca8f9a6359f7b.
Merge pull request #751 from unihorn/75

Revert "Merge pull request #631 from metaflow/fix-delete-key-as-director...