Add changelog for cherry-picked API fix from upstream

debian/changelog

+libheimdal-kadm5-perl (0.08-4) unstable; urgency=low
+
+  * Call the public kadm5_* API functions instead of the internal _c
+    versions, fixing a backward compatibility issue with the current
+    version of Heimdal in Debian.  (Closes: #686299)
+
+ -- Russ Allbery <rra@debian.org>  Thu, 30 Aug 2012 16:34:29 -0700
+
 libheimdal-kadm5-perl (0.08-3) unstable; urgency=low
 
   * Initial upload to Debian.  (Closes: #572400)