[segmentation] fix segment_id binarization
[segmentation] fix segment_id binarization

BUG=aomedia:1520

Change-Id: I5f746ab7217265b4de73eb40577db8ebb9e462ac

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom