Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "nsb_setup.sh: update to Ansible 2.3.2"
  - nsb_setup.sh: update to Ansible 2.3.2

    Change-Id: I2f700fbb169d02d126fe7ea22721bebf127c1206
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 68c26f9..5525e55 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 68c26f9b688181928ee5dbe92f95598f49c4e31b
+Subproject commit 5525e551cfecc9ac653778f3f498502b6922f2a8