Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Do not use shell to execute commands in tempest"
  - Do not use shell to execute commands in tempest

    Change-Id: I4d699481fdc63058c12ca9cfe18138e87025e9b3
    Signed-off-by: Juha Kosonen <juha.kosonen@nokia.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 7686014..613d6b4 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 768601416d408f8596f6d86f9abadbe13cf19c72
+Subproject commit 613d6b44998016ad84d87228cde53109fef0cc5f