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/parsermodule.c b/Modules/parsermodule.c
index 2ff67f2..6e52343 100644
--- a/Modules/parsermodule.c
+++ b/Modules/parsermodule.c
@@ -105,14 +105,14 @@
         }
 
         if (TYPE(n) == encoding_decl)
-            (void) addelem(v, i+1, PyBytes_FromString(STR(n)));
+            (void) addelem(v, i+1, PyString_FromString(STR(n)));
         return (v);
     }
     else if (ISTERMINAL(TYPE(n))) {
         PyObject *result = mkseq(2 + lineno + col_offset);
         if (result != NULL) {
             (void) addelem(result, 0, PyInt_FromLong(TYPE(n)));
-            (void) addelem(result, 1, PyBytes_FromString(STR(n)));
+            (void) addelem(result, 1, PyString_FromString(STR(n)));
             if (lineno == 1)
                 (void) addelem(result, 2, PyInt_FromLong(n->n_lineno));
             if (col_offset == 1)
@@ -689,7 +689,7 @@
             temp = PySequence_GetItem(elem, 1);
             if (temp == NULL)
                 return 0;
-            if (!PyBytes_Check(temp)) {
+            if (!PyString_Check(temp)) {
                 PyErr_Format(parser_error,
                              "second item in terminal node must be a string,"
                              " found %s",
@@ -714,10 +714,10 @@
                     Py_DECREF(o);
                 }
             }
-            len = PyBytes_GET_SIZE(temp) + 1;
+            len = PyString_GET_SIZE(temp) + 1;
             strn = (char *)PyObject_MALLOC(len);
             if (strn != NULL)
-                (void) memcpy(strn, PyBytes_AS_STRING(temp), len);
+                (void) memcpy(strn, PyString_AS_STRING(temp), len);
             Py_DECREF(temp);
         }
         else if (!ISNONTERMINAL(type)) {
@@ -800,10 +800,10 @@
             }
             if (res && encoding) {
                 Py_ssize_t len;
-                len = PyBytes_GET_SIZE(encoding) + 1;
+                len = PyString_GET_SIZE(encoding) + 1;
                 res->n_str = (char *)PyObject_MALLOC(len);
                 if (res->n_str != NULL)
-                    (void) memcpy(res->n_str, PyBytes_AS_STRING(encoding), len);
+                    (void) memcpy(res->n_str, PyString_AS_STRING(encoding), len);
                 Py_DECREF(encoding);
                 Py_DECREF(tuple);
             }