Update git submodules

* Update docs/submodules/yardstick from branch 'stable/danube'
  - Merge "Bugfix:HA test cases rely on dynamic ip addresses in fuel pods" into stable/danube
  - Bugfix:HA test cases rely on dynamic ip addresses in fuel pods

    JIRA: YARDSTICK-602

    change HA test cases to rely on dynamical generated pod.yaml in fuel pods

    Change-Id: I0efb01489eb2dd94babf1a45bff2fbf6adef5f6e
    Signed-off-by: JingLu5 <lvjing5@huawei.com>
    (cherry picked from commit 6c414e6f46861f71aa68db43ffabcad2305f3f32)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 53cae39..fd51e9f 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 53cae3915f9b49ada2095f3bd43c34d14c09e385
+Subproject commit fd51e9fe3f4c31be2cfd541f23c3bb5a7ba08291