Fix a CI_Input::set_cookie() bug

Found on StackOverflow: https://stackoverflow.com/questions/41925028/codeigniter-config-overrides-set-cookie-parameters
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index b1dadb1..28a8621 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -30,6 +30,7 @@
 -  Fixed a bug where :doc:`Session Library <libraries/sessions>` didn't read session data in a byte-safe manner when ``mbstring.func_overload`` is enabled.
 -  Fixed a bug (#4990) - :doc:`Profiler <general/profiling>` didn't close ``<pre>`` tags it generated.
 -  Fixed a bug (#4990) - :doc:`Profiler <general/profiling>` didn't HTML-escape quotes for ``$_SESSION`` variables.
+-  Fixed a bug where :doc:`Input Library <libraries/input>` method ``set_cookie()`` didn't allow its *httponly* and *secure* parameters to be overriden to ``FALSE``.
 
 Version 3.1.3
 =============