Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "tc053 kill haproxy wrong mismatch"
  - tc053 kill haproxy wrong mismatch

    JIRA: YARDSTICK-831

    Change-Id: I587c486572f439952b8a31da664d1e2c1fb8dc27
    Signed-off-by: rexlee8776 <limingjiang@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 9894640..af3e090 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 9894640fb446b587c621804572eb580886bae7a1
+Subproject commit af3e090dfcf2448d828308ca83ee79fdbd386245