Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Update the fuel pod.yaml"
  - Update the fuel pod.yaml

    Fuel except Controller and Compute nodes
    it deploys an ODL node in noHA and HA deployment
    and also a Gateway node in a noHA deployment.
    So it is essential to describe them in Fuel's pod.

    JIRA: YARDSTICK-1050

    Change-Id: Iee6c25c5b2e2e4e661ceb0591bf2437f7f7fa7f8
    Signed-off-by: Dimitrios Markou <mardim@intracom-telecom.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 3a5627e..31efe64 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 3a5627e416d68e2ba6a170750a680403ad8a1b6d
+Subproject commit 31efe64526ae5250b103a313c3041baa79864b5f