Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Remove unused nova client functions." into stable/fraser
  - Remove unused nova client functions.

    Following funtions are not required by shade client also
    not been used in any of the scenario files:
    *create_aggregate
    *create_aggregate_with_host
    *create_instance
    *add_host_to_aggregate
    *create_aggregate_with_host
    *get_availability_zones
    *get_availability_zone_names
    *remove_hosts_from_aggregate
    *remove_host_from_aggregate
    *delete_aggregate
    *get_image_by_name
    *check_status

    JIRA: YARDSTICK-1088

    Change-Id: I7ba0fbce6aa3e636aa55581a993c1ec1b48fbead
    Signed-off-by: Shobhi Jain <shobhi.jain@intel.com>
    (cherry picked from commit 2ca15a8c87e171cbd82b1e748dfc60903662b73b)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 8ebc5f4..5bbd425 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 8ebc5f4ac22fdaf493f2120997afdb5f3a6c10c1
+Subproject commit 5bbd425f239f9ebf2426ea07f6333f5492660e76