Update git submodules

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

    Change-Id: Ic3aa4bea2b546c95ce8187927a5762009adbd429
    Signed-off-by: Aric Gardner <agardner@linuxfoundation.org>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 38ca028..b59416c 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 38ca028551d2e498fdfe41627f8bf79a43a6a0fa
+Subproject commit b59416c7bc7227204ad855a94875cafc6455abce