Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Bugfix: HA test case baremetal down ipmi power off failed - dovetail"
  - Bugfix: HA test case baremetal down ipmi power off failed - dovetail

    Test case tc025 baremetal down failed to ipmi power off the node.
    This patch target to solve:
        ipmi_password is not correctly fetched

    JIRA: YARDSTICK-1326

    Change-Id: Ia915cd07cba420643fa9a679975178328be55700
    Signed-off-by: rexlee8776 <limingjiang@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index c8f14ff..8c470c7 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit c8f14ff70975ec178c33f8537dd8d4d5b46c82d9
+Subproject commit 8c470c7ae7ffccc06a7dada3eda9689d50d6ba89