Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Add Docker build opts

    Change-Id: I91fcb833b6b6216338b4fcb888f093a2086264a7
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit 9545e4cd5f16805adf2caadf348432ca1e8d9cd7)

diff --git a/docs/submodules/functest b/docs/submodules/functest
index a8ee3e0..8d28a82 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit a8ee3e0ce732793124a2cf2114ddcd3ccc724503
+Subproject commit 8d28a8282aaf9aa738e7d43c2bf65ec0d4f20b6a