Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Merge "[Functest] Provide credentials to Functest as a volume"
  - [Functest] Provide credentials to Functest as a volume

    The OpenStack credentials shall be fetched from jjob
    and provided to Functest as a docker volume.
    This way, Functest framework doesn't need to do it.
    It will assume the RC file is already present.

    Change-Id: I7a94ffffaefe65911594a9894b60b10cd13735ad
    Signed-off-by: jose.lausuch <jose.lausuch@ericsson.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 69331f6..b78fb39 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 69331f6c49393aa501d3ee1982870edd97d8e63f
+Subproject commit b78fb39202a79da6b88cede2da4dac696b31011f