kernel32: Fix required buffer length for locale values from registry

[Alexandre Julliard]

Nikolay Sivov <nsivov at codeweavers.com> writes:

> http://bugs.winehq.org/show_bug.cgi?id=32169
>
> Locale info to override is stored as REG_SZ and supposed to be
> null-terminated,

They are supposed to, but it's not guaranteed. The code should be able
to cope with non-terminated strings.

-- 
Alexandre Julliard
julliard at winehq.org