Use builtin macro for returning None

Signed-off-by: Lumir Balhar <lbalhar@redhat.com>
Signed-off-by: Jiri Kastner <jkastner@redhat.com>
diff --git a/python-schedutils/schedutils.c b/python-schedutils/schedutils.c
index 79fb0bd..a82b878 100644
--- a/python-schedutils/schedutils.c
+++ b/python-schedutils/schedutils.c
@@ -220,8 +220,7 @@
 	if (sched_setscheduler(pid, policy, &param) < 0)
 		return PyErr_SetFromErrno(PyExc_OSError);
 
-	Py_INCREF(Py_None);
-	return Py_None;
+	Py_RETURN_NONE;
 }
 
 static PyObject *get_priority(PyObject *self __unused, PyObject *args)