Update git submodules

* Update docs/submodules/releng from branch 'master'
  to c71ac3ec38b528a23a306830559207516a1cd7c1
  - Update Functest containers for OVN gates

    It has been updated to OpenStack master.
    OVN was merged in Neutron tree and the last tempest tests was fixed
    in master (to Full CNTT Compliance).

    Change-Id: I76e78cfa09c9398ef074456424041b9d689c0801
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index eef4064..c71ac3e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit eef406411b743963a9d60c10667671fc3a1b6296
+Subproject commit c71ac3ec38b528a23a306830559207516a1cd7c1