Fixed #21446 -- Allowed not performing redirect in set_language view

Thanks Claude Paroz and Tim Graham for polishing the patch.

docs/releases/1.10.txt

@@ -267,6 +267,10 @@ Internationalization
   :func:`~django.conf.urls.i18n.i18n_patterns` to ``False``, you can allow
   accessing the default language without a URL prefix.
 
+* :func:`~django.views.i18n.set_language` now returns a 204 status code (No
+  Content) for AJAX requests when there is no ``next`` parameter in ``POST`` or
+  ``GET``.
+
 Management Commands
 ~~~~~~~~~~~~~~~~~~~
 
@@ -695,6 +699,9 @@ Miscellaneous
   :meth:`~django.test.Client.login()` method no longer always rejects inactive
   users but instead delegates this decision to the authentication backend.
 
+* :func:`django.views.i18n.set_language` may now return a 204 status code for
+  AJAX requests.
+
 .. _deprecated-features-1.10:
 
 Features deprecated in 1.10