[Samba] Bad substitution for %a variable

[Walter.Laub at schwindt.net]

Hi,

The %a variable is not well substituted for XP64.

For separation of profiles of different OS we use the %a variable:
        logon path = \\%L\Profiles\%U\%a

With samba3021b the variable points to Win2K for XP64! This result in 
trouble with the user profiles!

Walter