Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 9aec98597417238ccd75fe0640f1cc8c0c4c5ea2
  - Remove tox-pip-version

    Change-Id: I7b8f4279d870e895a69322c6eca238c55f77a4f0
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e6189c9..9aec985 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e6189c9f5211c64bc0dc146ccf65762805969b33
+Subproject commit 9aec98597417238ccd75fe0640f1cc8c0c4c5ea2