Do not support package selection and upgrade in Qubes

anaconda/installclasses/qubes.py

@@ -48,6 +48,10 @@ class InstallClass(BaseInstallClass):
 
     bootloaderTimeoutDefault = 5
 
+    # Qubes comes preinstalled and does not support upgrade
+    showPackageSelection = False
+    showUpgrade = False
+
     tasks = [(N_("Minimal"), ["core", "qubes"]),
              (N_("Desktop"),
               ["backup-client", "base", "compat-libraries", "fonts",

anaconda/iw/task_gui.py

@@ -703,5 +703,4 @@ class TaskWindow(InstallWindow):
         self.xml.get_widget("addRepoButton").connect("clicked", self._addRepo)
         self.xml.get_widget("editRepoButton").connect("clicked", self._editRepo, self.rs)
 
-        #return vbox
-        return None
+        return vbox