Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 9aabfee9ad45ba409721a1a609d58747efc4fcd9
  - Install google-cloud-sdk package

    gsutil is needed by nfvbench

    Change-Id: I26ec63c6548c19d22e103dab271ee0bbdec75e1e
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 5ec9777..9aabfee 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 5ec9777d5f756cf82987b2e47b15956f0e0d7ebd
+Subproject commit 9aabfee9ad45ba409721a1a609d58747efc4fcd9