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/Objects/bytes_methods.c b/Objects/bytes_methods.c
index 2d55601..de87905 100644
--- a/Objects/bytes_methods.c
+++ b/Objects/bytes_methods.c
@@ -462,11 +462,11 @@
 	Py_ssize_t i;
 
         /*
-	newobj = PyBytes_FromStringAndSize(NULL, len);
+	newobj = PyString_FromStringAndSize(NULL, len);
 	if (!newobj)
 		return NULL;
 
-	s = PyBytes_AS_STRING(newobj);
+	s = PyString_AS_STRING(newobj);
         */
 
 	Py_MEMCPY(result, cptr, len);
@@ -490,11 +490,11 @@
 	Py_ssize_t i;
 
         /*
-	newobj = PyBytes_FromStringAndSize(NULL, len);
+	newobj = PyString_FromStringAndSize(NULL, len);
 	if (!newobj)
 		return NULL;
 
-	s = PyBytes_AS_STRING(newobj);
+	s = PyString_AS_STRING(newobj);
         */
 
 	Py_MEMCPY(result, cptr, len);
@@ -520,10 +520,10 @@
 	int previous_is_cased = 0;
 
         /*
-	newobj = PyBytes_FromStringAndSize(NULL, len);
+	newobj = PyString_FromStringAndSize(NULL, len);
 	if (newobj == NULL)
 		return NULL;
-	s_new = PyBytes_AsString(newobj);
+	s_new = PyString_AsString(newobj);
         */
 	for (i = 0; i < len; i++) {
 		int c = Py_CHARMASK(*s++);
@@ -553,10 +553,10 @@
 	Py_ssize_t i;
 
         /*
-	newobj = PyBytes_FromStringAndSize(NULL, len);
+	newobj = PyString_FromStringAndSize(NULL, len);
 	if (newobj == NULL)
 		return NULL;
-	s_new = PyBytes_AsString(newobj);
+	s_new = PyString_AsString(newobj);
         */
 	if (0 < len) {
 		int c = Py_CHARMASK(*s++);
@@ -589,10 +589,10 @@
 	Py_ssize_t i;
 
         /*
-	newobj = PyBytes_FromStringAndSize(NULL, len);
+	newobj = PyString_FromStringAndSize(NULL, len);
 	if (newobj == NULL)
 		return NULL;
-	s_new = PyBytes_AsString(newobj);
+	s_new = PyString_AsString(newobj);
         */
 	for (i = 0; i < len; i++) {
 		int c = Py_CHARMASK(*s++);