Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge changes from topics 'YARDSTICK-1154', 'YARDSTICK-1160'

    * changes:
      Kubernetes API "delete_service" missing parameter
      Bump Kubernetes Python client to version 6.0.0
      Avoid "volumeMounts" with "configMap" fixed permissions

  - Kubernetes API "delete_service" missing parameter

    Kubernetes method "delete_service" calls core API function
    "delete_namespaced_service". The parameter "body" [1] is missing:

        :param V1DeleteOptions body: (required)

    [1] https://github.com/kubernetes-client/python/blob/6.0.0/kubernetes/client/apis/core_v1_api.py

    JIRA: YARDSTICK-1154

    Change-Id: I40bca2af0f5359eaa788d3b81d82897a770329f0
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
  - Bump Kubernetes Python client to version 6.0.0

    Bump Kubernetes Python client to version 6.0.0. This versions supports
    Kubernetes service from 1.4 to 1.10 (current version) [1].

    Current version of Kubernetes service: 1.10.2

    [1] https://github.com/kubernetes-client/python/tree/6.0.0#compatibility-matrix

    JIRA: YARDSTICK-1153

    Change-Id: I96e855a68e39b17af02cd362040f8c765a9531f0
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
  - Avoid "volumeMounts" with "configMap" fixed permissions

    To access to the container without using a password, the jumphost
    RSA public key is copied to each container, using "volumeMounts"
    defined as "configMap", to /root/.ssh/authorized_keys.

    To work properly, the following permissions must be set:
      - /root/.ssh: 700
      - /root/.ssh/authorized_keys: 600

    Because of [1][2], the mounted folders have fixed permissions and
    cannot be modified.

    [1]https://groups.google.com/forum/#!topic/kubernetes-dev/eTnfMJSqmaM
    [2]https://github.com/kubernetes/kubernetes/issues/28317

    JIRA: YARDSTICK-1149

    Change-Id: I821064da56699c5b4f509d233c33e55af119fd56
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 1119449..553ffef 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 111944995df899b3895a74fb7de3066d4f4a7bd3
+Subproject commit 553ffefcdaa3d4a0ae61f9ce233b620d51b91d51