Update changelog for 1.8.1.

debian/changelog

-tails (1.8.1) UNRELEASED; urgency=medium
+tails (1.8.1) unstable; urgency=medium
 
-  * Dummy entry for next release.
+  * Security fixes
+    - Upgrade Tor Browser to 5.0.6.
+    - XXX: packages (Linux?)
+
+  * Bugfixes
+    - Fix time synchronization in bridge mode by refreshing our patch
+      against Tor's AppArmor profile.
 
- -- Tails developers <tails@boum.org>  Fri, 18 Dec 2015 19:04:37 +0000
+ -- Tails developers <tails@boum.org>  Fri, 18 Dec 2015 19:05:18 +0000
 
 tails (1.8) unstable; urgency=medium