Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Handle certificate in shaker.py

    http://artifacts.opnfv.org/logs/functest/huawei-virtual2/2018-07-11_18-47-21/functest.log

    Change-Id: I9049a06031db2335410828ecb30e763077360bc3
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 8b912ce..2ad8f03 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 8b912cec489a96178fcac5667c03e20850149c3a
+Subproject commit 2ad8f039112977c4dfdf4389586df74263d753b6