MSI: Implementation of the MsiVerifyDiskSpace function

[Saulius Krasuckas]

* On Sun, 29 Jan 2006, Thomas Weidenmueller wrote:
> * MattK wrote:
> > ChangeLog:
> > Implementation of the MsiVerifyDiskSpace function
> 
> 1. GetDiskFreeSpace is called with a uninitialized buffer
> 2. GetDiskFreeSpaceEx should be used to support big partitions
> 3. missing error checks lead to bogus calculations
> 4. calculating whether there's enough space is completely wrong
  5. for unicodiness' sake we should use *W version of a functions, not *A