Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Resolve NameError in test_utils.py"
  - Resolve NameError in test_utils.py

    The import of the yardstick module was removed from test_util.py, which relied
    on this module location for a file name in
    test_import_modules_from_package_no_mod and test_import_modules_from_package.

    JIRA: YARDSTICK-1258
    Change-Id: I754dbadfb8d788236f354e9a0c1a61ad6c4abf70
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 39b3d9a..145b9b8 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 39b3d9ae8ff19a0d64bff0e874f05b6dbcc30b01
+Subproject commit 145b9b8e3b109f08ae2cfee6d0a81956ebd91860