Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Yardstick API architecture improvement"
  - Yardstick API architecture improvement

    JIRA: YARDSTICK-710

    Since we have the plan to upload api v2 and gui.
    We need to add put and delete method.
    So the architecture need to be improved.

    Change-Id: Ie20a79c26ef6c581897ce4e63980fa2895b162d2
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 7ee54db..7949507 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 7ee54db221fbb4173de011585a425f0750dd6ccf
+Subproject commit 7949507437f8b1b1d9100bd13cf2d90bae60279d