git-convert-cache: fix up file modes in trees too
git-convert-cache: fix up file modes in trees too

git-fsck-cache complains about some of the odder ones, and is quiet
about the old (S_IFREG | 664) case, but that's wrong too.

Converting the kernel tree is too painful right now, but at least we
know how to do it if we ever want to.

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git