fix incorrect warning when walking on a particular rev
when a directory was given instead of a file it reported
incorrectly 'No such file or directory in rev <rev>'
we test if the file is a prefix directory
#!/bin/sh
hg init
echo This is file a1 > a
hg add a
hg commit -m "commit #0" -d "1000000 0"
touch b
hg add b
rm b
hg commit -A -m"comment #1" -d "1000000 0"