Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Roll rally and rally-openstack

    It conforms with neutron gates (rally-task) by rolling rally* and by
    selecting last stable os-faults.

    [1] http://logs.openstack.org/22/613122/1/check/neutron-rally-task/61886e6/job-output.txt.gz

    Change-Id: Id26f3100a0bc8b68c4b1d44115345c69053dcc5d
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 3872290..aa6ee5d 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 3872290bb673513459588bbe83e65efc631615f7
+Subproject commit aa6ee5d5f9013da722643c5eca8396135d0191bc