Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Always redirect debug to /dev/stdout

    It's mostly impossible to analyse issues without stdout.

    Change-Id: I05b908d6d0bac2afa524745d205c8050d6f43ec5
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a3bd7f5..4818cd9 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a3bd7f544347cdd2c4811768bb7232a4b299bbce
+Subproject commit 4818cd9300b643d2af764639593632f2074e62d3