tests/test-audit-path

manifest: fix _search() corner-case

It failed when searching the empty string in the null revision.

#!/bin/sh

hg init

echo % should fail
hg add .hg/00changelog.i

mkdir a
echo a > a/a
hg ci -Ama
ln -s a b
echo b > a/b

echo % should fail
hg add b/b

echo % should succeed
hg add b

echo % should still fail - maybe
hg add b/b

exit 0