Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Clean all possible resources

    It checks all openstack resources before cleaning.
    It allows removing images even if the test fail quickly.

    Change-Id: I1763b8a70fa7ffeb03c435e8e775c7afd1a7adac
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 4fb7e13..6166caf 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 4fb7e1330137fb77ed1b29bbc7c1491b6e12d9b6
+Subproject commit 6166caffe31888ef237874fdcaf088ac4ff8d003