Update git submodules

Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Decrease Sampling interval - Invalid Port results" into stable/fraser
  - Decrease Sampling interval - Invalid Port results

    JIRA: YARDSTICK-1219

    The computed in/fwd throughputs displayed on the L2FWD,
    L3FWD and VPE dashboards. The computed value is likely
    4x the expected value.

    It is required to return sampling information form Generator AND VNF at
    least every  1 second.

    Change-Id: I4435fd05ba3116ead836843a4c2fce133b767a28
    Signed-off-by: Daniel Martin Buckley <daniel.m.buckley@intel.com>
    Signed-off-by: Emma Foley <emma.l.foley@intel.com>
    (cherry picked from commit 2d10b0bf7238f5417d46f89c76b856f7e345f738)
    Signed-off-by: Patrice Buriez <patrice.buriez@intel.com>
    (also picking from commit 68aaa8ce8b20ba39040aa2469b384f59709620a7)