Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Add the Barbican test suite

    It eases verifying the functionality of a barbican installation.

    Change-Id: Iac2144ae6ba4d61b2b37bb5c7a0359edb3f222a6
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index c510c3f..518ad1e 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit c510c3f912fe095af08705eb694bb1f0a226f38c
+Subproject commit 518ad1e201389ecef17c0770a94793315d0d0fd7