Update git submodules

* Update plugins/hooks from branch 'stable-2.16'
  to 16fbec698f99ff80fd415b82f662e0a9042cee3b
  - Add stub module for integration tests
    
    The initial version only includes an empty test. The purpose is only to
    ensure that the plugin can be loaded. The test fails if the fix that was
    done in change I621573b52 is reverted.
    
    Additional tests of the plugin's actual functionality may be added later.
    
    Bug: Issue 10132
    Change-Id: Ie64b2c686e8003b456fcad68de9e1c33a98fd2cc
    
diff --git a/plugins/hooks b/plugins/hooks
index afafce3..16fbec6 160000
--- a/plugins/hooks
+++ b/plugins/hooks
@@ -1 +1 @@
-Subproject commit afafce3ff48154a82f023e2f8e59baa6f66d397d
+Subproject commit 16fbec698f99ff80fd415b82f662e0a9042cee3b