Description of problem:
you can't select another keymap for vnc via runonce

Version-Release number of selected component (if applicable):
3.3.1-2

How reproducible:
always

Steps to Reproduce:
1.Select a shutdown vm
2. click "run once"
3. select display options "vnc"

Actual results:
you can just select vnc or spice, but not keyboard layout

Expected results:
you can also specify the keymap

Additional info:
This would be a cool feature.