BUG: Fix BinShrinkImageFilter for different input/output image types.

The input iterator needs to be defined over the correct type.

Change-Id: I4a47762b4cfdfbea56b144ed576064122c65eb18
Merge topic 'BinShrinkOutput_release'

0aa9686e BUG: Fix BinShrinkImageFilter for different input/output image types.