Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Avoid duplicating tempest section in rally.conf

    Change-Id: I79598cce2c7dfe0a2e969ddd32735c3eb189fa7a
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 1222e8c..8b912ce 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 1222e8c0f3699c5d74c54df11e5cdf00fd468b59
+Subproject commit 8b912cec489a96178fcac5667c03e20850149c3a