fix handling of files of unsupported type in the walk code if a file was of unsupported type, it was considered as 'seen' while walking. this way it was possible to have file in the dirstate not yielded by the walk function.

#!/bin/sh

mkdir t
cd t
hg init
echo "invalid" > .hg/hgrc
hg status 2>&1 |sed -e "s:/.*\(/t/.*\):...\1:"