Update git submodules

* Update docs/submodules/yardstick from branch 'stable/euphrates'
  - NSB PROX test hang fixes

    The PROX tests were hanging in the duration
    runner.

    These are fixes for various errors:

    raise error in collect_kpi if VNF is down

    move prox dpdk_rebind after collectd stop
    fix dpdk nicbind rebind to group by drivers

    prox: raise error in collect_kpi if the VNF is down
    prox: add VNF_TYPE for consistency

    sample_vnf: debug and fix kill_vnf
    pkill is not matching some executable names,
    add some debug process dumps and try switching
    back to killall until we can find the issue

    sample_vnf: add default timeout, so we can override
    default 3600 SSH timeout

    collect_kpi is the point at which we check
    the VNFs and TGs for failures or exits

    queues are the problem make sure we aren't silently blocking on
    non-empty queues by canceling join thread in subprocess

    fixup duration runner to close queues
    and other attempt to stop duration runner
    from hanging

    VnfdHelper: memoize port_num

    resource: fail if ssh can't connect
    at the end of 3600 second test our ssh connection
    is dead, so we can't actually stop collectd
    unless we reconnect

    fix stop() logic to ignore ssh errors

    Change-Id: I6c8e682a80cb9d00362e2fef4a46df080f304e55
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ddff978..8e35dc2 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ddff9781c46fc446380a378cbca40d9576e32b68
+Subproject commit 8e35dc2c45ec1897690173b374406a05b2132954