"Boot qubes from CD-ROM" shouldnt show the same qube as source

fixes: QubesOS/qubes-issues#9344
(cherry picked from commit 95a5c5b)

qubesmanager/bootfromdevice.py

@@ -105,6 +105,7 @@ def __init_buttons__(self):
         utils.initialize_widget_with_vms(
             widget=self.fileVM,
             qubes_app=self.qubesapp,
+            filter_function=(lambda x: x != self.vm),
             allow_internal=True
         )