Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 849155ca2c480e87a89106c44f7a94a2331594ae
  - Stop using $USER

    It fails if runner user is not jenkins-ci.

    Change-Id: Ie7918b6466a83c27a9980c9ea27dc5f96d913e0c
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index f922b5c..849155c 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit f922b5c7e83d0721aa7811c6cb0a1fa5d263b509
+Subproject commit 849155ca2c480e87a89106c44f7a94a2331594ae