Mac address changes to uppercase can break things

[btoneill]

Describe the bug
0.16.x added a .upcase to the mac address, this causes things to try to update the MAC address on the proxmox host and can cause hotplug errors.

To Reproduce
Steps to reproduce the behavior:

1. Update a host with a MAC address that is in lower case

Expected behavior
It should work

Screenshots
Task UPID:nnj2-pve2-2:000E9A1F:3D47CB1E:67057B07:qmconfig:100:foreman@pve: failed because 400 Parameter verification failed. net0: hotplug problem - error on hot-unplugging device 'net0'

[btoneill]

So, this might not be an issue. It might have been a strange state this particular box was in. Something with the state and changing from lower case to upper case was triggering it. So, not a product of just this change, but, this change in concert with some other state in proxmox.