Update git submodules

* Update docs/submodules/yardstick from branch 'stable/danube'
  - Bugfix: Local Openstack Operation in HA test frameworks

    JIRA: YARDSTICK-635

    Change-Id: Ic27517714db9325e7a3b1ef623c49af61c36b2b5
    Signed-off-by: tjuyinkanglin <14_ykl@tongji.edu.cn>
    (cherry picked from commit 2fb95fbb9380ea7ce92dcb32cd2f0789b9f91bdc)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 20f5b0a..1b267df 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 20f5b0a8580c0e8c659424bab434a0e30f3c88c1
+Subproject commit 1b267df54356da0cba66a33edaf68ee50ecee53d