[atomic] docker not starting on latest atomic?

[Colin Walters <walters verbum org>]

It's because docker.socket was dropped as a followup from:
https://lists.projectatomic.io/projectatomic-archives/atomic-devel/2015-January/msg00034.html

I've pushed:
https://git.fedorahosted.org/cgit/fedora-atomic.git/commit/?h=f21&id=74943022e587888149cec9ef7ab301b073f820f1

which should fix it when the next compose happens.