cmd: ensure create_full_path returns FALSE for all errors

[Frédéric Delanoy]

2011/6/4 Dan Kegel <dank at kegel.com>:
> 2011/6/4 Dan Kegel <dank at kegel.com>:
>> https://testbot.winehq.org/JobDetails.pl?Key=11484
>> It passes on all tested platforms.  Feel free to
>> submit along with your patch verbatim if it looks
>> sufficient to you.
>
> BTW it looks like cmd test suite completely ignores
> stderr, which explains why that test passes even though
> the error message produced by wine's cmd and native cmd
> are different.

BTW, there's a
+rem warning, don't run any tests that depend on %ErrorLevel% after this line
in your patch

Is there really no way to reset ErrorLevel to a sane value?

IMHO it makes more sense to use tests using ErrorLevel *after* its
correct behaviour has been demonstrated, if possible...