Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Run vnfs in parallel in gates

    All the vnfs are now running well in gates.
    Let's try to run them in parallel again to save time.

    Change-Id: I1bddf4ba28566a3ba28ffa07ad05bced8a4235b9
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 34180ff..2fed59b 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 34180ff2b4325960a6565f9d10ff04e6f85c0415
+Subproject commit 2fed59b78a0ccf62364a6af8722c194a0160375f