This reverts r63675 based on the discussion in this thread:

 http://mail.python.org/pipermail/python-dev/2008-June/079988.html

Python 2.6 should stick with PyString_* in its codebase.  The PyBytes_* names
in the spirit of 3.0 are available via a #define only.  See the email thread.
diff --git a/Modules/spwdmodule.c b/Modules/spwdmodule.c
index 221223e..d3f309a 100644
--- a/Modules/spwdmodule.c
+++ b/Modules/spwdmodule.c
@@ -60,7 +60,7 @@
 sets(PyObject *v, int i, char* val)
 {
   if (val)
-	  PyStructSequence_SET_ITEM(v, i, PyBytes_FromString(val));
+	  PyStructSequence_SET_ITEM(v, i, PyString_FromString(val));
   else {
 	  PyStructSequence_SET_ITEM(v, i, Py_None);
 	  Py_INCREF(Py_None);