Mark Tails 2.11 as released.

debian/changelog

-tails (2.11) UNRELEASED; urgency=medium
+tails (2.11) unstable; urgency=medium
 
   * Security fixes
     - Upgrade Tor Browser to 6.5.1 based on Firefox 45.8. (Closes:
@@ -117,7 +117,7 @@ tails (2.11) UNRELEASED; urgency=medium
     - Add retry magic for lost click when opening Tails' documentation
       from the desktop launcher. (Closes: #12131)
 
- -- Tails developers <tails@boum.org>  Mon, 06 Mar 2017 12:19:36 +0100
+ -- Tails developers <tails@boum.org>  Mon, 06 Mar 2017 17:14:52 +0100
 
 tails (2.10) unstable; urgency=medium