[fprint] aes2501 fix patch

[Daniel Drake]

Vasily Khoruzhick wrote:
> Here's fix for aes2501
> 
> aes2501 can be mounted 180 rotated (this happens on most part of laptops), so 
> driver should detetect whether sensor is 180degrees rotated and asseble 
> frames in right order. 

Thanks, applied!

I introduced a small modification to the way that img->flags is handled 
so that the standardized image is the right way up even when the 
original image is reversed. Can you check that the 
finger_standardized.pgm output file from examples/img_capture is the 
right way up on your laptop?

By 'right way up' I mean like this:
http://www.reactivated.net/fprint/wiki/Image:Aes2501_long_scan.gif

Thanks,
Daniel