Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Improve "get_server" function in Kubernetes context"
  - Improve "get_server" function in Kubernetes context

    When a kubernetes context is returning the node info it is
    assumed that the first port defined is the ssh port which may
    not be the case. This patch will address this issue by looking
    for a defined port 22.

    JIRA: YARDSTICK-1301

    Change-Id: I65dee1bcf62f21ebcaefeaa2666bb0ad53f3876c
    Signed-off-by: John O Loughlin <john.oloughlin@intel.com>