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 test
cd test
echo foo>foo
hg init
hg addremove
hg commit -m 1
hg verify
hg serve -p 20059 > /dev/null &
sleep 1 # wait for server to be started
cd ..
hg clone http://localhost:20059/ copy
cd copy
hg verify
hg co
cat foo
hg manifest
hg pull
kill $!