Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Stop running tests from tests/unit" into stable/fraser
  - Stop running tests from tests/unit

    Since all tests have been moved into yardstick/tests,
    temperary code to run tests in both tests and yardstick/tests
    should be removed.

    JIRA: YARDSTICK-837
    Change-Id: I3bf3c9ece9bc8457d992e53ee8cc5cadb1dec8f0
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>
    (cherry-picked from commit 64add9a435e9455b3bff6971d2717857cdce8193)