Revert "Merge pull request #4861 from obfusk/fix-tmpdir-delete"

This reverts commit 00e388a8977f519f077dda44aff2ddc4c1b9b05a, reversing
changes made to d1691c21c7c61b84c6c98169ca9e3195f8848510.
Merge pull request #4893 from mitchellh/sethvargo/revert_tmpdir_changes

Revert "Merge pull request #4861 from obfusk/fix-tmpdir-delete"