Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Ansible: fix lowercasing issue with ConfigParser"
  - Ansible: fix lowercasing issue with ConfigParser

    by default ConfigParser will lowercase everything,
    unless you override optionxform.

    also sort key value in inventory line for consistency

    https://docs.python.org/3/library/configparser.html#configparser.ConfigParser.optionxform

    Transforms the option name option as found in an input file or as passed in by
    client code to the form that should be used in the internal structures. The
    default implementation returns a lower-case version of option; subclasses may
    override this or client code can set an attribute of this name on instances to
    affect this behavior.

    You don’t need to subclass the parser to use this method, you can also set it
    on an instance, to a function that takes a string argument and returns a
    string. Setting it to str, for example, would make option names case sensitive:

    cfgparser = ConfigParser()
    cfgparser.optionxform = str

    Note that when reading configuration files, whitespace around the option names
    is stripped before optionxform() is called.

    YARDSTICK-833

    Change-Id: Ia1810b0c77922d84e11c9e538540b38816338593
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index edc45f4..3710899 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit edc45f4034d3f5b3d225b66da3839d4fe60f461f
+Subproject commit 3710899e8909f2800a872561a1d2ffa7732dd517