Update git submodules

* Update docs/submodules/releng from branch 'master'
  to fc68d1fd7d6e64d9cdd1fb141c9923cca617fbf9
  - Remove all Dovetail Jenkins Jobs

    They haven't been executed for a while and
    the project is inactive.

    We will revert them if Dovetail is back to
    active.

    Change-Id: Ia5e5d65b40ad414863974f115a8e1bf07493ea28
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 480bbef..fc68d1f 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 480bbef4fbe5b2ff73b1dccff4843357fc056e0c
+Subproject commit fc68d1fd7d6e64d9cdd1fb141c9923cca617fbf9