Description of problem:
Blank page is displayed, after trying to edit CPU/Memory of a VM,
created from a template without "spec.template.spec.domain.cpu" defined in its VM object.

Version-Release number of selected component (if applicable):
4.13

How reproducible:
100%

Steps to Reproduce:
1. Create a template without "spec.template.spec.domain.cpu" defined in its VM object
2. Create a VM from such a template
3. Click on "CPU | Memory" field to change it, in the VM Details tab/page

Actual results:
Blank page is displayed, error in browser console:
"Uncaught TypeError: vmDraft.spec.template.spec.domain.cpu is undefined"

Expected results:
Page is displayed correctly, modal to Edit CPU/Memory is opened, no error.