Kernel nightly snapshots..

I forget who it is that used to do the nightly snapshots for the BK kernels, but I _think_ it was David Woodhouse (every time I've blamed it on somebody, I've blamed the wrong person, so I'm probably off on this one too, but maybe I finally got it right).

I was wondering how to get that re-started.. It should be technically pretty easy, except I realized that my tree doesn't even have plain 2.6.11 in it. But I just fixed that in the tree, since I need such a baseline myself for my next release..

Anyway, I just pushed out a kernel tree that contains a tag of a _tree_ that points to the tree at the point of 2.6.11. I also had to teach fsck-cache about the fact that you can give it any kind of object to start your references at, and to make fsck-cache happy, you need to

	git-fsck-cache --unreachable HEAD v2.6.11

to tell it that the kernel tree now has an unconnected tree (described by the tag "v2.6.11-tree", and I made the appropriate entry for it in .git/refs/tags).

I also updated git-prune-script to not remove these kinds of things.

With this, it should be trivial to create snapshots with

	git-diff-tree -p v2.6.11 HEAD

or similar.

		Linus