convertsimple(): call PyErr_NoMemory() on PyMem_NEW() failure

Raise a more revelant error (MemoryError instead of TypeError)
diff --git a/Python/getargs.c b/Python/getargs.c
index 1806bf8..b4b5db2 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -1172,6 +1172,7 @@
                 *buffer = PyMem_NEW(char, size + 1);
                 if (*buffer == NULL) {
                     Py_DECREF(s);
+                    PyErr_NoMemory();
                     return converterr(
                         "(memory error)",
                         arg, msgbuf, bufsize);
@@ -1215,6 +1216,7 @@
             *buffer = PyMem_NEW(char, size + 1);
             if (*buffer == NULL) {
                 Py_DECREF(s);
+                PyErr_NoMemory();
                 return converterr("(memory error)",
                                   arg, msgbuf, bufsize);
             }