Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - constants: fix pylint warnings for OSError

    IOError and OSError are the same in Python 3?
    Anyway we want to ignore ENOENT, not EEXIST

    JIRA: YARDSTICK-1012
    Change-Id: Ia75e41fecce505685745e0099669e45f3e82a1be
    Signed-off-by: Ross Brattain <ross.b.brattain@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 3333efb..f1f059b 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 3333efb08ae1d4ee92ea5274f847aabfa95e3eec
+Subproject commit f1f059b05efbb4f31be4d82f93e1e901cf68b239