Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Update releng commit id

    It updates the releng commit id because SFC requires the patch
    "Execute ovs-logger cmds with sudo" [1].

    [1] https://gerrit.opnfv.org/gerrit/#/c/46239/

    Change-Id: I0e6116e831c6cd470ce19e81be13c743960e65aa
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index dc1c3a3..59e523c 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit dc1c3a39878d7442d6ce9d1c806811392bea5c60
+Subproject commit 59e523ca8473754c8a4b7bd986ae1d056e62c553