Update git submodules

* Update docs/submodules/releng from branch 'master'
  to b8a9f6d26b38813161ea690936e398117291b0e8
  - Merge "Allow overriding default XtestingCI version"
  - Allow overriding default XtestingCI version

    Change-Id: I84d6f78fa1706dd92c6dd79c1a2aabcedd23ebb2
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 282ecd3..b8a9f6d 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 282ecd3baacd3a3954cac7514d936a6b3011af13
+Subproject commit b8a9f6d26b38813161ea690936e398117291b0e8