Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Update blacklist about migration tests for rally

    The test NovaServers.boot_and_migrate_server needs at least 2 compute
    nodes:
    https://github.com/openstack/rally/blob/stable/0.9/rally/plugins/openstack/scenarios/nova/servers.py#L763-L765

    Change-Id: I4ddf99188094ced57225d886037b00e91f3b68e6
    Signed-off-by: Linda Wang <wangwulin@huawei.com>
    (cherry picked from commit 613c672ac166ca92ce1284131ec06446e07e0023)

diff --git a/docs/submodules/functest b/docs/submodules/functest
index f73a272..df48fcc 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit f73a27258427b33a261c3e103ec1da25ef5c026b
+Subproject commit df48fcce2ea7fea367789d9d7fd28996691accc4