Fix error reporting issue in gdb test.

Cython/Debugger/Tests/test_libcython_in_gdb.py

@@ -39,8 +39,8 @@ def print_on_call_decorator(func):
 
         try:
             return func(self, *args, **kwargs)
-        except Exception as e:
-            _debug("An exception occurred:", traceback.format_exc(e))
+        except Exception:
+            _debug("An exception occurred:", traceback.format_exc())
             raise
 
     return wrapper