Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Bugfix: fix the return value

    openstack_snapshot and openstack_clean should return 0 when they are run
    successfully.

    JIRA: FUNCTEST-835

    Change-Id: I3fcc24ab985de382e0e59b129cb467d66a9a0de2
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 6c6b03b..dc7f851 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 6c6b03b310cf60b251a52127901431f7d059e45f
+Subproject commit dc7f851b0c5412709b52396b0855c0572c904525