Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - NSB "Prox" : Cleanup duplicated traffic profile

    JIRA: YARDSTICK-848

    The NSB PROX MPLS test uses Binsearch traffic
    profile and the mpls traffic profile is a duplicate.

    Change-Id: Ie2124cebf306fd6917b70ecd7c23ae12ef4850dc
    Signed-off-by: Abhijit Sinha <abhijit.sinha@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ce52059..1b9cc8a 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ce52059f5f78912eeff2d97235c1028c218bf960
+Subproject commit 1b9cc8a38a4866797bd49d006e22607b348f42ac