Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "tc046 kill keystone process condition incorrect - dovetail"
  - tc046 kill keystone process condition incorrect - dovetail

    Change-Id: If01abfd5a99b4cea74f835e258f3a982af9446cd
    Signed-off-by: rexlee8776 <limingjiang@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index e87df6a..85b4cc5 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit e87df6a6bd84778ed108bf917676cb06797d6157
+Subproject commit 85b4cc5f7d9d4a53a58f117dbc133694e0abcbf3