Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Allow overriding the default role

    It allows testing controllers which implements other RBAC policies.
    Defining NEW_USER_ROLE=admin will easily raise side effects for
    orchestrators such as Juju and Cloudify.

    Change-Id: Ia78a25381aeb8aa81fd1872661629e1c08432b8f
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 5bd8c86..51f3e7a 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 5bd8c86c423e59c7a24b15b9855f9e04ba8500c5
+Subproject commit 51f3e7a3cc4409fb9dda03bffa1252a8660f38b0