[PATCH] Calculate file sha1 in block

[Harri Salokorpi]

Hello,

Fredrik Lundh wrote:
> (the overhead for "reimporting" a module is marginal; it boils down to a
> dictionary lookup and a fast assignment to a local variable)

This was a left-over from my performance tweaking that I forgot to remove.

For large file imports (12 x 50M) the difference was something around 
0-4%, which is ~statistical noise. Intuitively it should be more for 
large number of small files, but I have not tested this.

-Harri