Use 'host-model' CPU configuration for new VMs
Use 'host-model' CPU configuration for new VMs

This fixes the issue of VMs not booting on certain CPUs. The downside is
that users will now loose VMs' states if they change host CPU.

https://bugzilla.gnome.org/show_bug.cgi?id=720798

vbenes/gnome-boxes,vbenes/gnome-boxes