Update git submodules

* Update docs/submodules/releng from branch 'master'
  to ba48a39d65c472deff98d6b0df4c3e92e4b28870
  - Run Shaker and VNFs in Airship gates

    VM can now reach Internet and then they pass successfully [1].

    [1] https://build.opnfv.org/ci/view/airship/job/airship-latest-daily/8/

    Change-Id: I2564837f5441f116634ce8a23885ce30224fe79a
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index b7871b1..ba48a39 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit b7871b1916fc8941c39950a9fb05308432a3a065
+Subproject commit ba48a39d65c472deff98d6b0df4c3e92e4b28870