Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Merge "Complete caching images for vnf testcases"
  - Complete caching images for vnf testcases

    It conforms with snaps API for publishing local images.
    It completes [1] which only modifies the yaml files.

    [1] https://gerrit.opnfv.org/gerrit/#/c/39757/

    Change-Id: I325a245c0e7bb15bb1f9570996500573cfe257b0
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 0b46845..9a9856b 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 0b4684562fa417201477fc4643a4eb4025847a84
+Subproject commit 9a9856b49a1758501d11cb0a47c713f92c5adc11