Deletes the on-disk cache directory, deregisters it from the
session-end cleanup finalizer, and clears the path strings from
@cellmap. After cleanup, the cellmap entries will be
NULL and must be regenerated via get.map().
Deletes the on-disk cache directory, deregisters it from the
session-end cleanup finalizer, and clears the path strings from
@cellmap. After cleanup, the cellmap entries will be
NULL and must be regenerated via get.map().