Update git submodules

* Update docs/submodules/yardstick from branch 'master'
  - Merge "Add function to upload image from local/url in GUI"
  - Add function to upload image from local/url in GUI

    JIRA: YARDSTICK-782

    As user, we need to upload image from local/url.
    If upload image from local, user need to choose local image, then
    we will load it to openstack.
    If upload image from url, we will download it and load it to openstack.

    Change-Id: Ia9a42fda15a1dfc91476643635343a2f77a94a6b
    Signed-off-by: chenjiankun <chenjiankun1@huawei.com>

diff --git a/docs/submodules/yardstick b/docs/submodules/yardstick
index ffecd5b..f5a96ff 160000 (submodule)
--- a/docs/submodules/yardstick
+++ b/docs/submodules/yardstick
@@ -1 +1 @@
-Subproject commit ffecd5b84eecdb74d7534b801c1359251c34b34e
+Subproject commit f5a96ffd959b11a122c4beea1fc99c89f755678c