Update git submodules

* Update docs/submodules/functest from branch 'master'
  - Allow setting two image extra properties per testcase

    It conforms with the flavor extra specs model [1].

    [1] https://gerrit.opnfv.org/gerrit/#/c/60713/

    Change-Id: I1555a313aaf56ae47f9ad2a4529eb8b94e636c00
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>

diff --git a/docs/submodules/functest b/docs/submodules/functest
index 484acb3..8d3eb36 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit 484acb3716b6f6261793b8a6a0220cce62ccb0c3
+Subproject commit 8d3eb364d84f90b19f9e7234d01add8764843081