Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 6f3e9a91d632c56bb64932911aef3f1af17e90db
  - Allow overriding blacklist.yaml if OVN

    Change-Id: I3335e485a2c844b9035dd574546167ccc52b66a4
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index c71ac3e..6f3e9a9 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit c71ac3ec38b528a23a306830559207516a1cd7c1
+Subproject commit 6f3e9a91d632c56bb64932911aef3f1af17e90db