auto-t: don't clear out rules from hwsim object

This got added in the re-write but a __del__ method was also
added to the Rule class as well. This caused problems if hwsim
cleaned up since it removed the rules, which caused each rule
to call __del__. Since the rule had already been removed there
was no longer a DBus interface which raised an exception.

autotests/util/hwsim.py

@@ -274,10 +274,6 @@ class Hwsim(iwd.AsyncOpAbstract):
         self._rules = RuleSet(self, objects)
         self._radios = RadioList(self, objects)
 
-    def __del__(self):
-        for rule in self._rules.values():
-            rule.remove()
-
     @property
     def rules(self):
         return self._rules