Update changelog for 0.23.

debian/changelog

-tails (0.23) UNRELEASED; urgency=medium
-
-  * Dummy changelog entry for next release.
-
- -- Tails developers <tails@boum.org>  Fri, 14 Mar 2014 17:23:00 +0100
-
-tails (0.23~rc1) unstable; urgency=medium
+tails (0.23) unstable; urgency=medium
 
   * Major new features
     - Spoof the network interfaces' MAC address by default (Closes: #5421),
@@ -97,7 +91,7 @@ tails (0.23~rc1) unstable; urgency=medium
     - Add an anti-test to make sure the memory erasure test works fine.
     - A *lot* of bugfixes, simplifications and robustness improvements.
 
- -- Tails developers <tails@boum.org>  Thu, 06 Mar 2014 14:43:00 +0100
+ -- Tails developers <tails@boum.org>  Tue, 18 Mar 2014 00:58:50 +0100
 
 tails (0.22.1) unstable; urgency=medium