Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Remove prepare_env"
  - Remove prepare_env

    After moving the rally installation out of prepare_env
    It doesn't much sense to keep this script as it doesn't
    do useful things any more.

    Change-Id: I9ab3b2dd30c8ec0fbb825ee4302a83cce80f1cbe
    Signed-off-by: Jose Lausuch <jalausuch@suse.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 01a5192..71ba783 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 01a5192428eb99afcb94047e6faa54e1d57114d1
+Subproject commit 71ba783c1279370af035ff7cac2de7522e95de78