Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Add API(v2) to get all test suite"
  - Add API(v2) to get all test suite

    JIRA: YARDSTICK-747

    API: /api/v2/yardstick/testsuites
    METHOD: GET

    Change-Id: I2375b6d2ea54704f5a2328cc8110058af038e777
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index 0d77985..50be49a 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit 0d77985517a40c54a38a851729bdaa3741a81059
+Subproject commit 50be49a89258a373aa1bb61b9f7fd2f26f9241e8