Update git submodules

* Update plugins/hooks from branch 'master'
  to 4ed6ba03134f95ba7e31cde58f7e33edc72156a5
  - Merge branch 'stable-2.15'
    
    * stable-2.15:
      Improve hook debug documentation
      Increase timeout and non-zero exit logs to error level
    
    Change-Id: I35ce660c3bd3d062e488d1bef1a3f4a5df9e8f52
    
  - Merge branch 'stable-2.14' into stable-2.15
    
    * stable-2.14:
      Improve hook debug documentation
      Increase timeout and non-zero exit logs to error level
    
    Change-Id: Ic7dc9bc15c602c17171480ed5f507440b341d2df
    
  - Improve hook debug documentation
    
    - Mention that non-zero exit codes and timeouts are always logged
      at error level.
    
    - Clarify that all hook output, both on stdout and stderr, is logged
      at debug level.
    
    Change-Id: I92acf1e58a4c8b52b8c16f0e587a1f0d1a963ac0
    
  - Increase timeout and non-zero exit logs to error level
    
    These cases are errors, so it makes more sense to log at error level.
    
    Change-Id: I63eb945f1f6a3a5bffc24bfbf4a905f4d80d35a3
    
diff --git a/plugins/hooks b/plugins/hooks
index aa42524..4ed6ba0 160000
--- a/plugins/hooks
+++ b/plugins/hooks
@@ -1 +1 @@
-Subproject commit aa4252417f54e28db3a7fa1f98d9a06d8ce49465
+Subproject commit 4ed6ba03134f95ba7e31cde58f7e33edc72156a5