Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Config volume_device_name as vdc for fuel

    JIRA: FUNCTEST-947

    Change-Id: I69a83dc69eaa4379c630e201e837f29311c716b9
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 286a2f7..5de084c 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 286a2f76763fb80bf117a70b355785c5a64acfd3
+Subproject commit 5de084c996d949deb1b6804a1c244d9aeb4e6ea6