Update git submodules

* Update docs/submodules/releng from branch 'master'
  to b409b171494cd381536adf93a1bbbba61638c1f4
  - Create python symlink if needed

    Change-Id: Ibacfd16de9fcfa8be838b7917b099f55dd82d7a9
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 38e288b..b409b17 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 38e288baacf39ae0e6a96473fe1f199ed001e1d0
+Subproject commit b409b171494cd381536adf93a1bbbba61638c1f4