Curl in the coreos-install ignition template

[brianredbeard]

In the file platforms/metal/cl/coreos-install.yaml.tmpl#L23 curl is run without the --fail option. In this mode it will supply the remote error message as the output of the command:

Retrieved from an emergency shell:

# mnt /dev/disk/by-id/oem /mnt/oem
# cat coreos-ignition.json
404 page not found

[brianredbeard]

cc @dghubble (a point to know regarding retrieval, as useful in reference to Matchbox)

[dghubble]

Matchbox and other projects do use the --fail flag. Tectonic should probably do the same.

https://github.com/coreos/matchbox/blob/master/examples/ignition/install-reboot.yaml

[bgilbert]

Also, I don't think the udevadm settle is necessary.