virtinst.cpu: fix copy host cpu definition

Commit cac4ac14 updated cpu features to use XMLBuilder and this change
removes the 'Features' class.  There is no longer any '.names()'
method to return names, so just cycle through all features and use a
name attribute instead.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1240938

Signed-off-by: Pavel Hrdina <phrdina@redhat.com>

virtinst/cpu.py

@@ -104,8 +104,8 @@ class CPU(XMLBuilder):
 
         for feature in self.features:
             self.remove_feature(feature)
-        for name in cpu.features.names():
-            self.add_feature(name)
+        for feature in cpu.features:
+            self.add_feature(feature.name)
 
     def vcpus_from_topology(self):
         """