Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 6667fd1043d059eeee37acb189b25a17908e7777
  - Manage Functest smoke container in Airship gate

    Change-Id: I67fae46cc5b5a98affc5a6b1d590a79df7c985ef
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index aaa0052..6667fd1 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit aaa0052698d5e647b64767f3383af78c1b4c9baa
+Subproject commit 6667fd1043d059eeee37acb189b25a17908e7777