Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "Push Functest API doc to artifact"
  - Push Functest API doc to artifact

    Note that it is not the final goal
    The final goal is to integrate api doc into Functest
    developer guide
    This will be triggered from opnfvdocs and replace the current
    developer guide:
    http://docs.opnfv.org/en/stable-danube/submodules/functest/docs/testing/developer/devguide/index.html

    This patch allows to have an up-to-date api docs on the artifact after
    functest merge
    http://artifacts.opnfv.org/functest/docs/

    Change-Id: I91256add29ce9eadd66764c2234da1d60981dd31
    Signed-off-by: Morgan Richomme <morgan.richomme@orange.com>
    Signed-off-by: Sakala Venkata Krishna Rohit <rohitsakala@gmail.com>
    Signed-off-by: Morgan Richomme <morgan.richomme@orange.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 7da2325..26f55be 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 7da23259c30038ff2f69c36b2c7117e2d69820f1
+Subproject commit 26f55bef14c2fec7a0422bc757517b115b7870c8