Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Add Ansible executor class for node context

    import the AnsibleCommon class to execute Ansible playbooks

    Update node context support to use AnsibleCommon

    needs unittests

    We must call ansible-playbook as an executable, so we must create temp
    files for inventory, and for the playbooks.

    AnsibleCommon has evolved to be quite flexible, it auto-generates the
    inventory from the context['nodes'] and generates groups from the node
    Role.

    We also support either a single playbook filename, or a list of
    filenames.

    If given a list we dynamically generate a playbook that includes the
    other playbooks.

    We support adding any number of extra_vars using a temp JSON file.

    Also designed to be extended by subclassing.

    Change-Id: I5bd0a2b4547feaadd70b7e2b8801f19371b99df0
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ae6f51c..c2f99db 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ae6f51c15a61e345cdc609f372ad04859d2e999d
+Subproject commit c2f99db8b4d8f021b29a4e3aae483ba715936a66