Update git submodules

* Update docs/submodules/releng from branch 'master'
  to f9aadd16485c4359ccf69c982d6cc0513e37df48
  - Merge "Manage multiple slaves for functest"
  - Manage multiple slaves for functest

    It allows testing multiple Functest tags in parallel.

    Change-Id: I29708953095cfd93724c593b6af02f151c68e202
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 0f37513..f9aadd1 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 0f37513479346d80b3c4f80c2eed6b9e38ead0c9
+Subproject commit f9aadd16485c4359ccf69c982d6cc0513e37df48