Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Use glance to list images"
  - Use glance to list images

    1. Images list is not supported by novaclient 8.0.0
    2. It moves images list out of nova and into glance

    Change-Id: I2a2d40a2ca3a0cf1ebfb55697b3c58af8748a805
    Signed-off-by: Linda Wang <wangwulin@huawei.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index c8d5216..4252d17 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit c8d5216c01c42f0e090f9b441985f8ebc3eca0ed
+Subproject commit 4252d177e9ccb0e533b74751008d7f8d5ab57840