Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Add Xtesting gate jobs

    It conforms with the last updates of collivier.xtesting [1].

    [1] https://galaxy.ansible.com/collivier/xtesting

    Change-Id: Ie94990c872f079735a87ce67c8ffb9378559c016
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index b122d02..d1a590a 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit b122d02902ec0d1f3a205b55fe43b07e8ef7c6c1
+Subproject commit d1a590abb5d3f3e5c80cc195c7bc6438adcba62d