Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - BugFix: Fix to pod filename ext and prox path

    As per defect:
    - the "context:" stanza of every tc_prox_baremetal*.yaml"
     file has an incorrect pathname for the config file

    -  tc_prox_baremetal_binsearch.yaml and
    tc_prox_baremetal_ramp.yaml refer to
    "prox-baremetal.yml", which idoes not exist

    - incorrect prox bin path

    Resolution:
    - Unify the pod file name and path for all BM tests
    - Prox bin path changed to "/opt/nsb_bin/prox"

    Change-Id: I16b25189104ad5585ddc1c2c0dd71b3c4c2aecd3
    Signed-off-by: Abhijit Sinha <abhijit.sinha@intel.com>
    (cherry picked from commit 2ebe6693b09a221de154a697ba24817a61e8548d)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 269c070..6d170b5 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 269c070a51389914c87b8f2c66a199ecabb6c5bb
+Subproject commit 6d170b5075f5750ba34b4647830f4c96bf5379ed