ole32: fix offsets managment

[Rob Shearman]

2008/7/26  <f.dorin at free.fr>:
> It's my first patch. So, if something is wrong, don't hesitate to notify me !
>
> ChangeLog entry :
> * real name   : François DORIN
> * email       : f.dorin at free.fr
> * description : offsets can be negative. It is necessary to treat them as signed numbers to avoid unexpected behaviors.

Thank you for your first contribution, but first of all the subject
isn't correct as the patch is to rpcrt4 instead of ole32. Second of
all, the patch is not correct as it is widl that is generating the
wrong format string here:

http://www.winehq.org/pipermail/wine-patches/2008-June/056332.html
http://www.winehq.org/pipermail/wine-devel/2008-June/066587.html

-- 
Rob Shearman