Avoid attempts to stat() the contents of '', which could happen
when the root directory is empty. Additionally, remove the
unnecessary '_' stat optimization since it was confusing and
possibly throwing off the non-existent case.
[ew: fixed indentation, rewrote commit message]
Acked-by: Eric Wong <normalperson@yhbt.net> Signed-off-by: Michael J. Kiwala <mkiwala@genome.wustl.edu>