Use _PyObject_CallNoArg()

Replace:
    PyObject_CallFunctionObjArgs(callable, NULL)
with:
    _PyObject_CallNoArg(callable)
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index b198857..6003476 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -3197,7 +3197,7 @@
     PySSL_END_ALLOW_THREADS_S(pw_info->thread_state);
 
     if (pw_info->callable) {
-        fn_ret = PyObject_CallFunctionObjArgs(pw_info->callable, NULL);
+        fn_ret = _PyObject_CallNoArg(pw_info->callable);
         if (!fn_ret) {
             /* TODO: It would be nice to move _ctypes_add_traceback() into the
                core python API, so we could use it to add a frame here */