Update git submodules

Update git submodules

* Update docs/submodules/releng from branch 'master'
  to 5f6a517af6e95a95e8e5cbb59030ff276165a620
  - Print debug infos in functest-kubernetes jjbs

    It will help understanding why master junit files are not published [1]

    [1] http://artifacts.opnfv.org/functest-kubernetes/functest-kubernetes-opnfv-functest-kubernetes-healthcheck-latest-k8s_smoke-run-15/results/k8s_smoke/junit_01.xml

    Change-Id: Id74060f160bad0ca961a0d9dfa9b2b547494d994
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>