Update git submodules

* Update plugins/replication from branch 'stable-2.15'
  to 6acd8e6c042abe22c5c10973d96fbda7f979748a
  - Merge branch 'stable-2.14' into stable-2.15
    
    * stable-2.14:
      Make loggers private
    
    Change-Id: I2ebbad6da3509e2d62e8fb48ebba6d0a2caf4b7f
    
  - Make loggers private
    
    Loggers shouldn't be shared between classes and hence they should be
    private.
    
    Change-Id: Iadd54c73455665b53cf9b58918b2e8c5cf19357e
    Signed-off-by: Edwin Kempin <ekempin@google.com>
    
diff --git a/plugins/replication b/plugins/replication
index a62c3c3..6acd8e6 160000
--- a/plugins/replication
+++ b/plugins/replication
@@ -1 +1 @@
-Subproject commit a62c3c331e11d6477d04b6b3079346f0ea2bcd8f
+Subproject commit 6acd8e6c042abe22c5c10973d96fbda7f979748a