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/Python/future.c b/Python/future.c
index ba058b8..2c6aaa2 100644
--- a/Python/future.c
+++ b/Python/future.c
@@ -20,7 +20,7 @@
 	names = s->v.ImportFrom.names;
 	for (i = 0; i < asdl_seq_LEN(names); i++) {
                 alias_ty name = (alias_ty)asdl_seq_GET(names, i);
-		const char *feature = PyBytes_AsString(name->name);
+		const char *feature = PyString_AsString(name->name);
 		if (!feature)
 			return 0;
 		if (strcmp(feature, FUTURE_NESTED_SCOPES) == 0) {
@@ -59,7 +59,7 @@
 
 	static PyObject *future;
 	if (!future) {
-		future = PyBytes_InternFromString("__future__");
+		future = PyString_InternFromString("__future__");
 		if (!future)
 			return 0;
 	}