Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Https now works for artifacts.opnfv.org"
  - Https now works for artifacts.opnfv.org

    Also, I believe that https://artifacts.opnfv.org/
    now works behind the GFW  and so
    https://build.opnfv.org/artifacts.opnfv.org/index.html
    Will no longer be needed.

    Change-Id: I5ce850a0264a0d56d27756928f82c6c03868b622
    Signed-off-by: Aric Gardner <agardner@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 6ea4c53..9c32082 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 6ea4c53335840558ad40f874423c07619c510153
+Subproject commit 9c320823c2898c98628c8537c02d112a3f72d439