[MERGE][328007] Fixed problem with `log -p` and non-ascii content of files: show_diff should write the diff to exact [stdout] stream.

[Ian Clatworthy]

Alexander Belchenko wrote:

> I can change getattr to following code (if we want to be really paranoid):
> 
> 	if isinstance(to_file, codecs.StreamWriter):
> 		self.to_exact_file = to_file.stream
> 	else:
> 		self.to_exact_file = to_file

I think that it's worth being paranoid here.

Ian C.