Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Add support for restarting a service"
  - Add support for restarting a service

    JIRA: YARDSTICK-1138

    Change-Id: Id57defb574eb7e0f5be81b52803cdb05f46796ab
    Signed-off-by: Dimitrios Markou <mardim@intracom-telecom.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index c47c33e..245e2e7 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit c47c33e6071a14485929bb58ee6e1d2aaeff7243
+Subproject commit 245e2e7c3fe831027944709c7712e8552ef2e2fc