Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 15ed52e9184f7a807086750adfa37b2b34cd28ff
  - Temporarily clean the arm and arm64 jobs

    Change-Id: Idbcfcd3cd0b51f59359aec5e36359569e8856fbe
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 092082f..15ed52e 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 092082fafbe995283e7049a0b67a6736c71a3ed5
+Subproject commit 15ed52e9184f7a807086750adfa37b2b34cd28ff