Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Pull all containers before running tests

    Else we might test previous containers.

    Change-Id: I53b98f99f7fe5db8ea2087c93cfc58a03103db9e
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 69f3cc7..4754864 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 69f3cc73c8c88e51864297199b945568a7dc5ce2
+Subproject commit 475486404eaf7d89dbdafd9ce244efd824371777