Make the "clean checkout" detection actually work: reading a dir will *always* end with an ENOENT error. Expect that and disable the optimization only if something else happens.
Make the "clean checkout" detection actually work: reading a dir
will *always* end with an ENOENT error. Expect that and disable
the optimization only if something else happens.

* subversion/libsvn_client/update.c
  (is_empty_wc): check for the kind of error we received before
   possibly declaring the folder "unclean"

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion