Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Fix duplicate IMAGE_PROPERTIES env variable in functest run"
  - Fix duplicate IMAGE_PROPERTIES env variable in functest run

    Update envs only once with IMAGE_PROPERTIES and FLAVOR_EXTRA_SPECS
    if installer type is fuel or deploy scenario is ovs or fdio

    Change-Id: I7c1e997cf95d30972688e697574458a3a0f1e55c
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 04e66d8..84c13a0 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 04e66d80c9d2c6348f672bc6c90ea5bef9b0ffe4
+Subproject commit 84c13a04a8682b4c413ff587a963f4fdd67cc550