Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 39beb5abc16b178edfa9afa9823b36b77c6e1edd
  - Merge "Add Functest Xtesting git repo in scm"
  - Add Functest Xtesting git repo in scm

    Change-Id: I92ffd069e5160f62cd5436804cd299ad08e13a15
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index f16b81e..39beb5a 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit f16b81e1240fba7e98a72981d160f1838d82918d
+Subproject commit 39beb5abc16b178edfa9afa9823b36b77c6e1edd