Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Replace cinder detach volume with shade client." into stable/fraser
  - Replace cinder detach volume with shade client.

    Function detach volume now uses shade client.

    JIRA: YARDSTICK-891

    Change-Id: Ie437ccf1172cb82dc869963f0d62e31a5ab23ebb
    Signed-off-by: Shobhi Jain <shobhi.jain@intel.com>
    (cherry picked from commit f6cca46f6b1aa6134a0e634a3a9e524cdbbfa729)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 61f64de..3de47d0 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 61f64de8a22c78a5cb81acd60bbc5ed7489b211c
+Subproject commit 3de47d08fc211cc2afdcf7a0411e84fc9ae3f948