Update git submodules

* Update docs/submodules/releng from branch 'master'
  to bff8119cdf465d38ec05a8310847117f713bd159
  - Remove former kuberef and nfvbench jobs

    Change-Id: If67babfc60f911911e07f279b919aea201aa1dd5
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 4325db5..bff8119 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 4325db541cfdb83ebec3bc3551fa7f6084d5e647
+Subproject commit bff8119cdf465d38ec05a8310847117f713bd159