Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Remove obsolete iptable rules"
  - Remove obsolete iptable rules

    It simply breaks parallel testing and seems useless/deprecated.

    Change-Id: I7dafa65f4acfdabb089cf0e10c66d5eb632500c6
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 7d6d736..9705226 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 7d6d7362966db61f94db6f1035a258468cf6efdc
+Subproject commit 9705226e4b6f530508697a2206a758a522b5e97b