Module `directory` used to set AUTO_NAME_DIRS. This was changed in
73e94b84 but README.md hasn't been updated. This looks like an
accidental omission that this commit fixes.
This was ported from Oh-My-Zsh and since have been disabled in it.
Explained in more detail
rvm/rvm/issues/3091#issuecomment-60083194
Related: #998, #1081