NetworkManager and network services both enabled in Fedora Atomic

[Dusty Mabe]

Both NetworkManager and network systemd services are enabled in F21
and F22 Atomic and this could be causing some issues we are seeing. 
We should probably open a BZ for this. If no one objects I will make
one.

I would suggest that we adopt the approach that Fedora Cloud Base
takes by just having the Network service enabled. This would also mean
we can pull the NetworkManager packages out of atomic and make the
image smaller.

Thoughts?

Dusty