Bad KVM test w.r.t. networking

[Tim Penhey]

While looking at this bug:

kvmBrokerSuite worker/provisioner: tests are poorly isolated
https://bugs.launchpad.net/juju-core/+bug/1474946

I came across this function: EnsureRootFSEtcNetwork

Which was getting called from the KVM broker tests.
However it was adding /etc/network to the LXC root dir. This is never
going to have any impact.

I have renamed the function and stopped calling it from the kvm broker
test as shown here:
  http://reviews.vapour.ws/r/2190/diff/#

However I feel there may be a hole now in the KVM networking testing.

Can someone who knows what they are doing take a look please?

Cheers,
Tim