Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - bugfix: tc078 fails in some situations

    1. make  "SPECint_benchmark, runspec_iterations, runspec_tune, runspec_size,
    runspec_rate" parameterized and change the default value "int^429" to "int"
    2. remove "become: true" in some roles since it does not need root privilege

    JIRA: YARDSTICK-852

    Change-Id: Icb384bddc12911e2681a981d0504e0e142d1a8ec
    Signed-off-by: rexlee8776 <limingjiang@huawei.com>
    (cherry picked from commit 7bd43b239b7be6f478399526a177922d4482bcc2)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 7bad248..e7338e8 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 7bad2481c956956ce62eff953ae477333b6c4494
+Subproject commit e7338e897892b3d1c484379d8706e503bde684ab