Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 087aeb2a54d3d573bc095fdf3a0afcf36a2fd86e
  - Merge "Remove lfdocs_conf"
  - Remove lfdocs_conf

    This project is unmaintained and basically useless.

    Change-Id: I8d373a8365166af050b397a786e7ddb34f988256
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 0a758cc..087aeb2 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 0a758cc0a5a8c91346f1c237cc50d25e091df7bd
+Subproject commit 087aeb2a54d3d573bc095fdf3a0afcf36a2fd86e