Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Remove the former Dockerfile

    opnfv/functest had been split into multiple containers based on
    Alpine (See Docker Slicing [1]) during Euphrates.

    As ARM is being switching to them, we can safely remove the related
    files.

    [1] https://git.opnfv.org/functest/tree/docs/com/pres/dockerslicing/dockerslicing.md?h=stable/euphrates

    Conflicts:
        tox.ini
        setup.cfg

    Change-Id: I30294a94cc742ba80a7bc4f35db9330240385bb0
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit 0705a7ed15f090b3be64f2995d1c9fff51edc2f1)

diff --git a/docs/submodules/functest b/docs/submodules/functest
index f93c1aa..eccd246 160000 (submodule)
--- a/docs/submodules/functest
+++ b/docs/submodules/functest
@@ -1 +1 @@
-Subproject commit f93c1aa48e61e1ad23b54feab4fff6b3d9fe9f26
+Subproject commit eccd2461a9272191b1baa312624158de8da84fc9