Mark Tails 2.5 as released.

debian/changelog

-tails (2.5) UNRELEASED; urgency=medium
+tails (2.5) unstable; urgency=medium
 
   * Major new features and changes
     - Upgrade Icedove to 1:45.1.0-1~deb8u1+tails2. (Closes: #11530)
@@ -51,7 +51,7 @@ tails (2.5) UNRELEASED; urgency=medium
     - Bump a bunch of timeouts to cope with the occasional slowness on Jenkins.
     - Only query A records when exercising DNS lookups, to improve robustness.
 
- -- Tails developers <tails@boum.org>  Sun, 31 Jul 2016 08:55:45 +0000
+ -- Tails developers <tails@boum.org>  Sun, 31 Jul 2016 16:50:35 +0000
 
 tails (2.4) unstable; urgency=medium