Update git submodules

* Update docs/submodules/releng from branch 'master'
  - Add OPNRC file to Yardstick container for fuel installer type

    OPNRC file (openstack.creds) is needed to call openstack services
    It was not added any longer because we added a specific case for
    fuel installer to send SSH_KEY, OPNRC file and OS_CACERT to
    the container

    Change-Id: I235b138a77e06cded86a0b163ef383c1c37a0469
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>

diff --git a/docs/submodules/releng b/docs/submodules/releng
index 06bfdd1..f9fe2c8 160000 (submodule)
--- a/docs/submodules/releng
+++ b/docs/submodules/releng
@@ -1 +1 @@
-Subproject commit 06bfdd12f95942652ac3dc3cfe635fa72692d7cc
+Subproject commit f9fe2c801bc5420d17a36a3b43923b04b26e50fd