Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 8f421799c07dc1957fdd23dd8c355ec1ccf65642
  - Merge "nit: remove duplicate"
  - nit: remove duplicate

    Change-Id: I4bcc042f3b8b67b628ad02efb07c934a0f8445c1
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index a7c4b42..8f42179 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit a7c4b42c835048599ce24c6d2ab03205bd7c6a50
+Subproject commit 8f421799c07dc1957fdd23dd8c355ec1ccf65642