Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Use /root/.kube/config for all installers

    There is no reason to use one specific dir per installer in Functest
    containers.

    Change-Id: Ib2e1443b14c15aa385e65194f70f6442e0c9f7b9
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index c560df6..6f6cf24 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit c560df67104dde2734cb6962324a55e4c2420e33
+Subproject commit 6f6cf24f53add8df9cd976da3ba211ab564814fd