Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Remove 'inconsistent-return-statements' check from Pylint

    There are several bugs in Pylint [1] [2] affecting
    'inconsistent-return-statements' check. It will be temporarily
    removed.

    [1] https://github.com/PyCQA/pylint/issues/1782
    [2] https://github.com/PyCQA/pylint/issues/1794

    JIRA: YARDSTICK-911

    Change-Id: Ib655ef1befdc734c646cdfb9b48f1db0ccdf676d
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 753e8ad..fa3a7b8 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 753e8ad700f602c9b2804f212376d0ad8b14ca6d
+Subproject commit fa3a7b8d6cadbb2d5e9311cb2da040003f9b9140