google-calendar: Log writing to the tokens file.

Author: Niloth-p

zulip/integrations/google/get-google-credentials

@@ -63,6 +63,7 @@ def get_credentials(
                 creds = flow.credentials
             else:
                 creds = flow.run_local_server(port=0)
-        with open(tokens_path, "w") as token:
-            token.write(creds.to_json())
+        with open(tokens_path, "w") as token_file:
+            token_file.write(creds.to_json())
+            logging.info("Saved tokens to %s", tokens_path)
     return creds