Update the changes file for bug7799.

Still not sure it's actually fixed yet...

changes/bug7799

@@ -1,3 +1,7 @@
  o Minor changes (log clarification)
    - Add more detail to a log message about relaxed timeouts. Hopefully
      this additional detail will allow us to diagnose the cause of bug 7799.
+ o Minor bugfixes
+   - Don't attempt to relax the timeout of already opened 1-hop circuits.
+     They might never timeout. This should eliminate some/all cases of
+     the relaxed timeout log message.