cmd: ensure create_full_path returns FALSE for all errors

[Dan Kegel]

2011/6/4 Frédéric Delanoy <frederic.delanoy at gmail.com>:
> On Sat, Jun 4, 2011 at 19:27, Dan Kegel <dank at kegel.com> wrote:
>> Please add a test case, too.
>
> OK. Do I need a testbot account as well?

Yeah.  The cmd test suite is touchy, so
it's worth it to use testbot to verify your
test before you send it to wine-patches.

I threw an example test case together for you.
A quick run on xp seems to indicate you also need to set errorlevel,
so I added that.   See the patch attached to
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.

(Oddly, windows xp's cmd doesn't seem to set errorlevel
if you use rmdir on a nonexistent directory...)
- Dan