Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Build functest-parser for arm64 via travis-ci

    Even if clearwater-live-test dependencies have been updated [1], the
    next containers can be built for ARM (ruby raises SEGFAULT via
    qemu-user-static):
      - functest-vnf
      - functest-restapi

    The related manifest is also updated.

    [1] https://gerrit.opnfv.org/gerrit/#/c/50295/8

    Conflicts:
        .travis.yml

    Change-Id: Ie1eb78436a3da5eb7b5c1028b7f8323e8c3e73a2
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>
    (cherry picked from commit 12c99c5f3fef126283e3a9795c4c1d436cc7846f)