Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Use assertIn(x, y) instead of other variations"
  - Use assertIn(x, y) instead of other variations

    unittest.assertIn(x,y) should be used instead of:
    * unittest.assertTrue(x in y)
    * unittest.assertEqual(x in y, True)

    Also fixes pep8 violations existing in the file.

    Change-Id: I705c1bd4af74757b5c928995894aede436d66817
    JIRA: YARDSTICK-901
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 7f8f31c..7602ac5 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 7f8f31cf68dbecaf521348fccf540cbe0e7c72bd
+Subproject commit 7602ac57877300e2a7fbfc86f5688faa0e2fe4f5