Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "collectd: write config file from Jinja2 template"
  - collectd: write config file from Jinja2 template

    We have the collectd.conf inside the python package
    so instead of copying it from various places,
    write the template directly to the remote system.

    collectd: read collect.conf template with pkgresources

    read the collectd.conf file as a string directly
    and upload without creating temp file

    use Jinja2 template, disable failing plugins

    use proper Jinja2 template, disable the plugins that
    were failing to load and blocking startup

    add support for per-testcase collectd.conf config
    using YAML

    add support for custom interval, default is 25 seconds

    Change-Id: Id904f7b7c9f41a9dd7adf5dfa06c064d65c25d2d
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index bd33c3f..804a541 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit bd33c3fee8d285dba5f190de0af2eb62ba7f04b2
+Subproject commit 804a541be394f794047a55091c9378c605e9e7ec