MSI: fix some NULL checking in MSI_RecordGetStringA

[James Hawkins]

On Tue, Dec 16, 2008 at 11:59 AM, Aric Stewart <aric at codeweavers.com> wrote:
> Ok,  Though it mirrors what is happening over in MSI_RecordGetStringW so i
> assumed it was just a few check that had been accidentally forgotten.
>

Yea, I'm sure it's right, but it's nice to verify those changes with
tests and to keep it from regressing.

-- 
James Hawkins