Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Bugfix: KeyError when using http dispatcher"
  - Bugfix: KeyError when using http dispatcher

    JIRA: YARDSTICK-632

    When we use http dispatcher to output yardstick result.
    It can upload data, but when we query the data, it get a KeyError.

    Change-Id: I5410c207c68cff2621ff8184ae17daa4c286cea5
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index bd76fc2..a34afb3 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit bd76fc20362d5cf0ff67e8c5b29cbdd034d8b23c
+Subproject commit a34afb31bd142a798ba2c4b4ceb125cf74274dc8