Boot order specified on the OS is deprecated for at least a decade

[ekohl]

From https://issues.redhat.com/browse/SAT-41340?focusedId=28854878&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-28854878

fog-libvirt creates boot ordering as follows:

<boot dev='network'/>
<boot dev='hd'/>

This is obsolete for at least a decade.

It's implemented here:

fog-libvirt/lib/fog/libvirt/models/compute/server.rb

Lines 302 to 304 in faa507b

	boot_order.each do |dev|
	xml.boot(:dev => dev)
	end

The current way is to add <boot order='$priority'/> to devices (disk, cdrom, nic) instead, like this:

<interface type='network'>
  <mac address='52:54:00:26:79:99'/>
  <source network='default'/>
  <model type='virtio'/>
  <boot order='1'/>
  <address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</interface>