Update git submodules

* Update docs/submodules/releng from branch 'master'
  to e1f021c2d45e25e1ab13637f410d325f934bcd15
  - Try to get best parallel testing values

    It's no simple to get the best threads (test cases and tempest) values
    and then guarantee Functest vs:
      - test flapping
      - backend limitations

    As opposed to the OpenStack gates, Jenkins runs all test cases in
    parallel which indirectly increases the number of threads.

    Let's run smoke sequentially which is closed to the OpenStack model.

    Change-Id: I6172568b915d49e2723173b7c428970110f63620
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index e3d6986..e1f021c 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit e3d698634d0d751ebd4d9701c134af03bb5852b7
+Subproject commit e1f021c2d45e25e1ab13637f410d325f934bcd15