Fixed the way dom0/domU xen role is defined in the setup module

library/setup

@@ -711,10 +711,11 @@ class LinuxVirtual(Virtual):
     def get_virtual_facts(self):
         if os.path.exists("/proc/xen"):
             self.facts['virtualization_type'] = 'xen'
+            self.facts['virtualization_role'] = 'guest'
             if os.path.exists('/proc/xen/capabilities'):
+                for line in open('/proc/xen/capabilities'):
+                    if "control_d" in line:
                         self.facts['virtualization_role'] = 'host'
-            else:
-                self.facts['virtualization_role'] = 'guest'
                     
         elif os.path.exists('/proc/vz'):
             self.facts['virtualization_type'] = 'openvz'