Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 5d590607f6678f853538d3942036a5ba3d3ae45f
  - Enable cntt RC-1 gate job for Airship

    pod 15 hw issue has been resolved and RI-1 site manifests have been
    upgraded to Airship 1.8 (OPNFV Jerma+)

    Signed-off-by: James Gu <james.gu@att.com>
    Change-Id: I84a334e4bb2a3f4a148bc3654da4e97a993d9697

diff --git a/docs/submodules/releng b/docs/submodules/releng
index f4c43a0..5d59060 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit f4c43a00986c4fdc1cfdcc3e1d3cdaae9e4aec51
+Subproject commit 5d590607f6678f853538d3942036a5ba3d3ae45f