bpo-37316: mmap.mmap() passes the wrong variable to PySys_Audit() (GH-14152)

Also, add a missing call to va_end() in PySys_Audit().

Python/sysmodule.c

@@ -182,6 +182,7 @@ PySys_Audit(const char *event, const char *argFormat, ...)
         va_list args;
         va_start(args, argFormat);
         eventArgs = Py_VaBuildValue(argFormat, args);
+        va_end(args);
         if (eventArgs && !PyTuple_Check(eventArgs)) {
             PyObject *argTuple = PyTuple_Pack(1, eventArgs);
             Py_DECREF(eventArgs);