Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 6a2179b439f501d25513cce1f0df8f6f312b9e46
  - Fix typo in Functest container builds

    Change-Id: Ib101eca6d7e6d887feee9eec6bc9d3c90af3d05f
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 7a300e6..6a2179b 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 7a300e64dddc158c6941e6bfd3b6fa66233a7561
+Subproject commit 6a2179b439f501d25513cce1f0df8f6f312b9e46