Fix var name in product_payment_to_mixpanel

apps/payment/tasks.py

@@ -21,12 +21,12 @@ def transaction_to_mixpanel(user_id, amount, time, product_type):
 @app.task
 def product_payment_to_mixpanel(user_id, event_name, time, properties):
     mix = Mixpanel(settings.MIX_TOKEN)
-    properties = {
+    props = {
         '$time': time,
     }
-    properties.update(properties)
+    props.update(properties)
     mix.track(
         user_id,
         event_name,
-        properties=properties,
+        properties=props,
     )