Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "[Bug Fix] Support nova create instance operation"
  - [Bug Fix] Support nova create instance operation

    Add the ability to create a nova instance through the
    operation perspective

    JIRA: YARDSTICK-1038

    Change-Id: Idac141958d65cc6c53b6bd27df83ac74ae8804ec
    Signed-off-by: Dimitrios Markou <mardim@intracom-telecom.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 108749a..8eefd8a 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 108749ac9b0063f94296df1f487841c9b384811b
+Subproject commit 8eefd8ac17fb25c6bcfa219e64a1ad7a81961c40