Mark Tails 2.7.1 as released.

debian/changelog

-tails (2.7.1) UNRELEASED; urgency=medium
+tails (2.7.1) unstable; urgency=medium
 
   * Security fixes
     - Upgrade Tor Browser to 6.0.7 (build3) based on Firefox 45.5.1.
@@ -46,7 +46,7 @@ tails (2.7.1) UNRELEASED; urgency=medium
       the same thing, but also offers an interactive Ruby shell, via
       pry, with the Cucumber world context.
 
- -- Tails developers <tails@boum.org>  Wed, 30 Nov 2016 14:02:15 +0100
+ -- Tails developers <tails@boum.org>  Wed, 30 Nov 2016 17:27:37 +0100
 
 tails (2.7) unstable; urgency=medium