Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Update samples/test_suite.yaml" into stable/fraser
  - Update samples/test_suite.yaml

    The sample test suite at sample/test_suite.yaml contained incorrect
    syntax. It has been updated to add the "default" parameter to
    "task_args" when running a testcase.

    JIRA: YARDSTICK-1125
    Change-Id: I53409168e47d969317145623df1e2c789396cc32
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>
    (cherry picked from commit 7b00d64494bdd61f2ab37005de76fa5f6496d45d)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 9809527..594d939 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 98095278d8f21271399a2a9c80d380fef65013e5
+Subproject commit 594d939576ca463e94f2906bc38b4866fd9a64eb