Updated changelog

Author: Edward J M Easton

CHANGES.md

@@ -7,6 +7,8 @@
     by 9x
   * Bugfix: authenticate should propagate non-OperationFailure exceptions
     (e.g. ConnectionFailure) as this might be indicative of socket failures
+  * Bugfix: return 'deleted' state in VersionStore.list_versions() so that
+    callers can pick up on the head version being the delete-sentinel.
 
 ### 1.10 (2015-10-28)
 
@@ -64,4 +66,4 @@
 
 ### 1.0 (2015-06-14)
 
-  *  Initial public release
+  *  Initial public release