core/xen: setup xen-specific defaults in separate settings file

core/settings-xen-Linux.py

@@ -0,0 +1,8 @@
+#!/usr/bin/python2
+
+from __future__ import absolute_import
+
+from qubes.storage.xen import QubesXenVmStorage
+
+def apply(system_path, vm_files, defaults):
+    defaults['storage_class'] = QubesXenVmStorage

rpm_spec/core-dom0.spec

@@ -200,6 +200,9 @@ fi
 %{python_sitearch}/qubes/storage/*.py
 %{python_sitearch}/qubes/storage/*.pyc
 %{python_sitearch}/qubes/storage/*.pyo
+%{python_sitearch}/qubes/settings.py
+%{python_sitearch}/qubes/settings.pyc
+%{python_sitearch}/qubes/settings.pyo
 %{python_sitearch}/qubes/qmemman*.py*
 %{python_sitearch}/qubes/modules/0*.py*
 %{python_sitearch}/qubes/modules/__init__.py*