Update git submodules

* Update plugins/replication from branch 'stable-2.16'
  to 8fdb0f9ac0a7f68b3f942cb4a9fd4c94e488ab57
  - ReplicationStorageIT: Wait for all pushes without order
    
    Some tests don't have a predefined order for which events will be
    replicated first. Using a timeout based on a single replication event is
    flawed when we don't know the expected order. Instead, use a timeout for
    the group of events and ignore the order.
    
    For two events replicating to a single remote with a single thread, we
    expect the complete replication to take twice as long. Two events
    replicating to two remotes will use one thread each and therefore not
    take any longer than the single remote case.
    
    Change-Id: Ieb21b7eee32105eab5b5a15a35159bb4a837e363
    
diff --git a/plugins/replication b/plugins/replication
index 53e083f..8fdb0f9 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit 53e083fd0f17d1403b4d150e66655907c1ea139d
+Subproject commit 8fdb0f9ac0a7f68b3f942cb4a9fd4c94e488ab57