Update git submodules

* Update docs/submodules/yardstick from branch 'stable/fraser'
  - Merge "Add "duration" parameter to test case definition" into stable/fraser
  - Add "duration" parameter to test case definition

    Add "duration" parameter to test case definition, in scenario:options
    section. This parameter will be rendered in the traffic profile.

    If the parameter is not present in the test case scenario options, the
    default time written in the traffic profile options will be 30 seconds
    (TrafficProfile.DEFAULT_DURATION = 30). If the traffic profile
    injection time is not defined, the default injection time will be 30
    seconds.

      testcase:scenario:options:duration (default = 30)
          render --> traffic_profile:duration
              parse --> TrafficProfile.duration (default = 30)

    Target traffic profiles (RFC2544):
      - RFC2544Profile
      - IXIARFC2544Profile

    JIRA: YARDSTICK-1194

    Change-Id: I968922e6bb882d7ee15aa1c4db4037face7a3492
    Signed-off-by: Rodolfo Alonso Hernandez <rodolfo.alonso.hernandez@intel.com>
    (cherry picked from commit 1517319fd210d71db72c5e4bfa00fc49ae4fa877)

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index dbdd0a3..ab5bb7f 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit dbdd0a395616495b41d35d904fb5fb4da4544d26
+Subproject commit ab5bb7fab516b88a668e9450fbd5ef086bfc06fc