Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "task: don't hide exceptions in Task"
  - task: don't hide exceptions in Task

    If the Task raised an exception we currently hide it
    and replace it with RuntimeError.  This is bad.

    If an exception occured, then we don't have a result so
    re-raise the original exception.

    Or we could log the traceback and raise RuntimeError, but
    that doesn't seem to be a good idea.

    Sample traceback after re-raising original.  Without this patch the ValueError is only written
    to _write_error_data

    2018-03-25 22:57:56,511 yardstick.benchmark.contexts.node node.py:85 DEBUG BareMetals: []
    2018-03-25 22:57:56,511 yardstick.benchmark.contexts.node node.py:89 DEBUG Env: {}
    2018-03-25 22:57:56,511 yardstick.cmd.commands.task task.py:57 INFO Task FAILED
    Traceback (most recent call last):
      File "/home/rbbratta/yardstick-upstream/yardstick/yardstick/cmd/commands/task.py", line 54, in do_start
        result = Task().start(param, **kwargs)
      File "/home/rbbratta/yardstick-upstream/yardstick/yardstick/benchmark/core/task.py", line 103, in start
        task_args_fnames)
      File "/home/rbbratta/yardstick-upstream/yardstick/yardstick/benchmark/core/task.py", line 321, in _parse_tasks
        task_args_fnames[i]
      File "/home/rbbratta/yardstick-upstream/yardstick/yardstick/benchmark/core/task.py", line 558, in parse_task
        context.init(cfg_attrs)
      File "/home/rbbratta/yardstick-upstream/yardstick/yardstick/benchmark/contexts/heat.py", line 131, in init
        server = Server(name, self, server_attrs)
      File "/home/rbbratta/yardstick-upstream/yardstick/yardstick/benchmark/contexts/model.py", line 210, in __init__
        (name, p))
    ValueError: server 'trafficgen_1', placement 'pgrp2' is invalid
    2018-03-25 22:57:56,512 yardstick.cmd.commands.task task.py:62 INFO Task FAILED
    2018-03-25 22:57:56,662 yardstick.benchmark.runners.base base.py:124 DEBUG Terminating all runners
    NoneType

    JIRA: YARDSTICK-1102

    Change-Id: I7e6fa41fc1d36f6d438a1602ab60cb41ffbee1e9
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 374a6ca..0cfb413 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 374a6caf766c0503f114a83cc20144f72b10ab45
+Subproject commit 0cfb413451484e311ad5d3e956f3bb9c52f6978e