virDomainEventCallbackListFree: Don't leak @list->callbacks

The @list->callbacks is an array that is inflated whenever a new event
is added, e.g. via virDomainEventCallbackListAddID(). However, when we
are freeing the array, we free the items within it but forgot to
actually free it.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
(cherry picked from commit ea13a759)

src/conf/domain_event.c

@@ -147,6 +147,7 @@ virDomainEventCallbackListFree(virDomainEventCallbackListPtr list)
             (*freecb)(list->callbacks[i]->opaque);
         VIR_FREE(list->callbacks[i]);
     }
+    VIR_FREE(list->callbacks);
     VIR_FREE(list);
 }