Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - Merge "Adding vFirewall HTTP Traffic Profiles." into stable/euphrates
  - Adding vFirewall HTTP Traffic Profiles.

    Modified http_locator location for 64K, 256K, 512K and 1024K
    concurrency files.

    The traffic profiles include various http locator image sizes i.e
    4K,64K,256K,512K and 1024K

    The traffic schema is changed to "nsb" from "isb" for all the
    traffic profiles

    Change-Id: I012da8daaa880ca80db2d3b08cebd9a73c19cd47
    Signed-off-by: Phani Kiran Thaticharla <phani.kiran.thaticharla@intel.com>
    Reviewed-by: Oscar Medina-Duran <oscar.medina-duran@intel.com>
    Reviewed-by: Deepak S <deepak.s@linux.intel.com>
    Reviewed-by: Ross Brattain <ross.b.brattain@intel.com> 
    (cherry picked from commit bb2da407193d6a5747cf15069d61cceb4c6bf1f7)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 9e5870b..49cb31a 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 9e5870ba9aeed6cc7e5be92d17165130f4e121d4
+Subproject commit 49cb31a0e2e2ccafd6785a5f966d4f66e5c19bcf