"git-checkout-cache -f -a" failure

[Morten Welinder <mwelinder@gmail.com>]

git-checkout-cache is having problems when files change from directories to
plain files or vice versa.  cg-seek seems to be similarly affected.

Note also, that  git-checkout-cache's error messages haven't caught up with
the command renaming.

Morten


cd /tmp
mkdir xxx
cd xxx
rm -rf .git empty yyy 
touch empty
cg-init </dev/null
cg-tag initial
mkdir yyy
touch yyy/zzz
cg-add yyy/zzz 
cg-commit </dev/null
cg-tag dir
rm -rf empty yyy
rm -f .git/HEAD
cat .git/refs/tags/initial > .git/HEAD 
git-read-tree -m HEAD
git-checkout-cache -f -a
touch yyy
cg-add yyy
cg-commit </dev/null 
cg-tag file
# Got that?

# yyy is a file right now.
git-read-tree `cat .git/refs/tags/dir`
git-checkout-cache -f -a
# error: checkout-cache: unable to create file yyy/zzz (Not a directory)
# Not good!

rm -rf empty yyy
git-read-tree `cat .git/refs/tags/dir`
git-checkout-cache -f -a

# yyy is a directory right now
git-read-tree `cat .git/refs/tags/file`
git-checkout-cache -f -a
# error: checkout-cache: unable to create file yyy (Is a directory)
# Not good!