core: fix QubesVm.clone_attrs - really copy dicts

Otherwise it would point at the same object and for example changing
vm.services[] in one VM will change that also for another. That link
will be severed after reloading the VMs from qubes.xml, but at least in
case of DispVM startup its too late - vm.service['qubes-dvm'] is set for
the DispVM template even during normal startup, not savefile preparation.

core-modules/000QubesVm.py

@@ -1210,7 +1210,10 @@ class QubesVm(object):
         self._do_not_reset_firewall = True
         for prop in self.get_clone_attrs():
             try:
-                setattr(self, prop, getattr(src_vm, prop))
+                val = getattr(src_vm, prop)
+                if isinstance(val, dict):
+                    val = val.copy()
+                setattr(self, prop, val)
             except Exception as e:
                 if fail_on_error:
                     self._do_not_reset_firewall = False