Revert "Seed specific Fedora network configuration"

This reverts commit 4ba28063a7a2f976e6cab3a48e81ea74a18ef6fb.

The new plan is to use the DIB baremetal element to enable
stable interface names by default on all distros... so
no need to disable them as a special case for the seed.

Change-Id: I57284f86988a634275d3b93f9eb37d69a9e3c156
Add set -eux

This script should be set -e. Also added -ux for good measure. On RHEL,
os-refresh-config was failing to run due to a missing requirements.txt line on
argparse (separate patch), however the failure was not failing the image build
b/c this script was not -e.

Change-Id: Id36d61442d8104cada8346f47e63858cf7f08096
Merge "Add set -eux"
Merge "Revert "Seed specific Fedora network configuration""