Fix broken test due to refactoring.

common/djangoapps/student/tests/test_login.py

@@ -188,7 +188,7 @@ class LoginTest(TestCase):
         response = client1.post(self.url, creds)
         self._assert_response(response, success=True)
 
-        self.assertEqual(self.user.profile.get_meta()['session_id'], self.client.session.session_key)
+        self.assertEqual(self.user.profile.get_meta()['session_id'], client1.session.session_key)
 
         # second login should log out the first
         response = client2.post(self.url, creds)