systemd landed

[Colin Walters <walters verbum org>]

I've pushed commits to poky and gnome-ostree to do the systemd switch:

https://github.com/cgwalters/poky/commit/a1c4e77596ffb8e634016aea37d96c54196c548a
http://git.gnome.org/browse/gnome-ostree/commit/?id=5f8465c3b6b276dc33dc89fc67c678835065edc6

Works here in a local build and qemu, I'll have the ostree.gnome.org
builder work on it overnight.

While this isn't perfect, I think I'd rather get things mostly working
in a new state rather than try to change everything at once. 

Incidentally, OSTree is great for doing UsrMove - you don't download
changed files, stuff just gets hardlinked in a different place, there's
no evil hacks to move files around, and it's all fully atomic to
upgrade!  Win.

As far as the system state, note that for the moment you will need to
log in as root and start gdm manually:

systemctl start gdm

Also, the terrible "ginitscripts" hack which asked you to make a user is
gone now too.  You have to log in as root and run:

useradd foo
passwd foo

Where "foo" should typically be the same username/uid as from your host
system.

One other thing I should highlight: "ostadmin" is now "ostree admin".

http://git.gnome.org/browse/ostree/commit/?id=fa5485c6c4e77a0d161a502d3efb806d6d803f19

As far as what doesn't work - I need to work on ensuring that /var is
initialized with empty directories (e.g. /var/log/gdm).  Previously this
lived in ginitscripts, so if you have an old deployment it will boot,
but fresh ones won't.