auto-t: add more cleanup to ofono based tests (again)

The AuthCenter was still not being fully cleaned up in these
tests. It was being stopped but there was still a reference being
held which prevented __del__ from being called.

autotests/testEAP-AKA-ofono/connection_test.py

@@ -61,6 +61,7 @@ class Test(unittest.TestCase):
         IWD.clear_storage()
 
         cls.auth.stop()
+        cls.auth = None
 
 if __name__ == '__main__':
     unittest.main(exit=True)

autotests/testEAP-AKA-prime-ofono/connection_test.py

@@ -60,6 +60,7 @@ class Test(unittest.TestCase):
     def tearDownClass(cls):
         IWD.clear_storage()
         cls.auth.stop()
+        cls.auth = None
 
 if __name__ == '__main__':
     unittest.main(exit=True)

autotests/testEAP-PEAP-SIM/connection_test.py

@@ -44,26 +44,26 @@ class Test(unittest.TestCase):
 
 
     def test_connection_success(self):
-        auth = AuthCenter('/tmp/hlrauc.sock', '/tmp/sim.db')
-
         ofono = Ofono()
         ofono.enable_modem('/phonesim')
         ofono.wait_for_sim_auth()
 
         wd = IWD(True)
 
-        try:
         self.validate_connection(wd)
-        finally:
-            auth.stop()
 
     @classmethod
     def setUpClass(cls):
+        cls.auth = AuthCenter('/tmp/hlrauc.sock', '/tmp/sim.db')
+
         IWD.copy_to_storage('ssidEAP-PEAP-SIM.8021x')
 
     @classmethod
     def tearDownClass(cls):
         IWD.clear_storage()
 
+        cls.auth.stop()
+        cls.auth = None
+
 if __name__ == '__main__':
     unittest.main(exit=True)

autotests/testEAP-SIM-ofono/connection_test.py

@@ -62,6 +62,7 @@ class Test(unittest.TestCase):
         IWD.clear_storage()
 
         cls.auth.stop()
+        cls.auth = None
 
 if __name__ == '__main__':
     unittest.main(exit=True)