Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 1f93df139b36df565a538c28ef1b0fbfe0a0f576
  - Publish airship gate job

    It allows verifying Airship changes via Functest.
    It also removes all Functest features testcases which are useless here.

    Change-Id: I5e466e3d1e4f3bd637cf3ec6951f031e0cc3b0ac
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index c5077b9..1f93df1 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit c5077b9384624acd51f65c394ff930d71d01f8a5
+Subproject commit 1f93df139b36df565a538c28ef1b0fbfe0a0f576