Update changelog with #11910 merge.

debian/changelog

 tails (2.7) UNRELEASED; urgency=medium
 
-  * Major new features and changes
-    - Upgrade Icedove to 1:45.4.0-1~deb8u1+tails1. (Closes: #11854,
-      #11860)
-
   * Security fixes
     - Upgrade to Linux 4.7. (Closes: #11885, #11818)
     - Upgrade to Tor 0.2.8.9. (Closes: #11832, #11891)
+    - Upgrade Tor Browser to 6.0.6 based on Firefox 45.5. (Closes: #11910)
+    - Upgrade Icedove to 1:45.4.0-1~deb8u1+tails1. (Closes: #11854,
+      #11860)
     - Upgrade imagemagick to 8:6.8.9.9-5+deb8u5.
     - Upgrade openssl to 1.0.1t-1+deb8u5.
     - Upgrade libarchive to 3.1.2-11+deb8u3.