Remove internal qubes from being target of ask

For: QubesOS/qubes-issues#1512

Author: ben-grande

qrexec/policy/parser.py

@@ -1875,6 +1875,14 @@ def collect_targets_for_ask(self, request):
         if source_uuid in targets:
             targets.remove(source_uuid)
 
+        for unwanted_target in targets.copy():
+            if unwanted_target.startswith("@dispvm:"):
+                unwanted_target_name = unwanted_target[len("@dispvm:"):]
+            else:
+                unwanted_target_name = unwanted_target
+            if info[unwanted_target_name].get("internal", False):
+                targets.remove(unwanted_target)
+
         return targets