Fix non-empty $CDPATH causing failed tests.
If CDPATH contains '.', every cd command prints the target path,
which causes additional output in tests and makes them fail.
#!/bin/sh
hg init dir
cd dir
echo bleh > bar
hg add bar
hg ci -m 'add bar'
hg cp bar foo
echo >> bar
hg ci -m 'cp bar foo; change bar'
hg debugrename foo
hg debugindex .hg/store/data/bar.i