Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Add new glance scenarios for rally 0.10"
  - Add new glance scenarios for rally 0.10

    Some new glance scenarios have been added in Rally stable/0.10 [1].

    [1]: https://github.com/openstack/rally/releases/tag/0.10.0

    Co-Authored-By: Juha Kosonen <juha.kosonen@nokia.com>
    Change-Id: I91ffe31b8cc5c94991c9bdd6e33b756c447d82ce
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 9407ead..2c58114 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 9407ead03ef8f89479383d1144a52fc2f35fd9f6
+Subproject commit 2c581142ad3524b23e109c25d9a1dc2a1ae16514