Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "run_traffic: capture and exit gracefully if crash in trex run_traffic"
  - run_traffic: capture and exit gracefully if crash in trex run_traffic

    new non-blocking code of run_traffic has raise condition which causes
    trex client to exit with STLError. This patches captures the exception
    and exit gracefully

    Traceback (most recent call last):
    File "/usr/lib/python2.7/multiprocessing/process.py", line 258, in
    _bootstrap
    self.run()
    File "/usr/lib/python2.7/multiprocessing/process.py", line 114,
    in run
    self._target(*self._args, **self._kwargs)
    File
    "/opt/nsb_bin/yardstick_venv/lib/python2.7/site-packages/yardstick-0.1.dev0-py2.7.egg/yardstick/network_services/vnf_generic/vnf/sample_vnf.py",
    line 945, in _traffic_runner
    self.resource_helper.run_traffic(traffic_profile)
    File
    "/opt/nsb_bin/yardstick_venv/lib/python2.7/site-packages/yardstick-0.1.dev0-py2.7.egg/yardstick/network_services/vnf_generic/vnf/sample_vnf.py",
    line 506, in run_traffic
    self._run_traffic_once(traffic_profile)
    File
    "/opt/nsb_bin/yardstick_venv/lib/python2.7/site-packages/yardstick-0.1.dev0-py2.7.egg/yardstick/network_services/vnf_generic/vnf/tg_rfc2544_trex.py",
    line 63, in _run_traffic_once
    self.client.stop(self.my_ports)
    File
    "/opt/nsb_bin/trex/scripts/automation/trex_control_plane/stl/trex_stl_lib/trex_stl_client.py",
    line 1202, in wrap2
    raise STLError("'{0}' - connection to the server had been lost: '{1}'".format(func_name, client.conn.get_disconnection_cause()))
    STLError:

    Change-Id: Ie5741339451e0a3f9c4bb48f64fd35d86d18e5d4
    Signed-off-by: Deepak S <deepak.s@linux.intel.com>
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 95d9798..641b528 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 95d9798e15d54270f73692b22b138b44f9defd7a
+Subproject commit 641b52820afd1c61261cda954803cc335b818ccc