Add forgotten changelog entries for Tails 2.10~rc1.

debian/changelog

@@ -30,7 +30,7 @@ tails (2.10~rc1) unstable; urgency=medium
       (Closes: #12012).
 
   * Security fixes
-    - Dummy.
+    - Upgrade Icedove to 1:45.6.0-1~deb8u1+tail1s.
 
   * Minor improvements
     - Enable and use the Debian Jessie proposed-updates APT
@@ -73,6 +73,7 @@ tails (2.10~rc1) unstable; urgency=medium
     - Raise the maximum number of loop devices to 32 (Closes: #12065).
     - Drop kernel.dmesg_restrict customization: it's enabled by
       default since 4.8.4-1~exp1 (Closes: #11886).
+    - Upgrade Electrum to 2.7.9-1.
 
   * Bugfixes
     - Tails Greeter: