Fix handling of paths when run outside the repo. The main problem was that dirstate.getcwd() returned just "", which was interpreted as "we're at the repo root". It now returns an absolute path. The util.pathto function was also changed to deal with the "cwd is an absolute path" case.

#!/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