[PATCH] Fix util._statfiles_clustered() failing at root of awindows drive

[Andrei Vermel]

> Yes, your previous message made things much clearer. I am 
> currently stuck on "_statfiles_clustered('\\a')" which is 
> valid but fails with your patch for dir[-1] is undefined. I 
> think the right fix is to replace empty dir by current driver 
> letter + ':\', I am looking for an efficient way to do that.
I mean change
dir, base = nf[:pos], nf[pos+1:]
to
dir, base = nf[:pos+1], nf[pos+1:]