RT3334: Fix crypto/LPdir_win.c

Reviewed-by: Richard Levitte <levitte@openssl.org>
Reviewed-by: Andy Polyakov <appro@openssl.org>
(cherry picked from commit 6a14fe7576e7a14a46ba14df8be8fe478536b4fb)
Followup on RT3334 fix: make sure that a directory that's the empty
string returns 0 with errno = ENOENT.

Reviewed-by: Andy Polyakov <appro@openssl.org>
(cherry picked from commit 360928b7d0f16dde70e26841bbf9e1af727e8b8f)