We recently changed the ref for atomic host in Fedora 26 to be
`atomic-host` rather than `docker-host`.
Similarly we'd like to change the name of the file within the repo 
from fedora-atomic-docker-host.json to fedora-atomic-host.json.
If anyone is pulling from this repo and building trees please update
your files to use the new filename for the master and f26 branches.
We have temporarily left a symlink for compatibility. I'll be removing
that in a week or two and updating this mail when that happens.