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/_heapqmodule.c b/Modules/_heapqmodule.c
index aa5bbb1..7a64161 100644
--- a/Modules/_heapqmodule.c
+++ b/Modules/_heapqmodule.c
@@ -687,6 +687,6 @@
 	m = Py_InitModule3("_heapq", heapq_methods, module_doc);
 	if (m == NULL)
     		return;
-	PyModule_AddObject(m, "__about__", PyBytes_FromString(__about__));
+	PyModule_AddObject(m, "__about__", PyString_FromString(__about__));
 }