Depending on whether QEMU actually supports the option, we can put the
'rendernode' on the '-display egl-headless' cmdline.
https://bugzilla.redhat.com/show_bug.cgi?id=1628892
Signed-off-by: Erik Skultety <eskultet@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>