Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Enable tempest run concurrently

    Append a guid to the end of names of resources created for tempest,
    including project, user, network, images and flavors.

    Change-Id: I01fc7c5cb45cd5724a99ba1d220c3f3f7d6639cf
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index f45b958..3945146 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit f45b9587c5568c0b64cfedb94e4241e485ffce47
+Subproject commit 3945146d7448ba57b79dd4c350ce7f8881661a8e