rename "ugly path" directory to remove path > 100 character warning in R CMD build

Without this change the following warning occurs during R CMD build:

Warning in utils::tar(filepath, pkgname, compression = "gzip", compression_level = 9L,  :
  storing paths of more than 100 bytes is not portable:
  ‘packrat/tests/testthat/Ugly, but legal, path for a project (it's pretty long too, I hope that's okay)/oatmeal/DESCRIPTION’