Update git submodules

Update git submodules

* Update docs/submodules/functest from branch 'stable/euphrates'
  - Build vnf and restapi containers for ARM

    The root cause of the problem was the installation
    of unf_ext packet. The Gemfile.lock in
    https://github.com/boucherv-orange/clearwater-live-test
    asked for version 0.0.6 and this version was not found for arm.
    When it tried to build the package, the conversion from int
    to char error was thrown (issue reported here
    https://github.com/knu/ruby-unf_ext/issues/15).

    As now version 0.0.7.4 is selected, then the vnf docker
    images are built without any other errors.

    Gemfile.lock was updated in the original repo,
    this fix enables vnf and restapi containers build for ARM.

    JIRA: FUNCTEST-899

    Change-Id: Id2c5fe82cb3705f58a8175fcf0a17f443e9b7d9d
    Signed-off-by: Delia Popescu <delia.popescu@enea.com>
    (cherry picked from commit 63ec3c39ef720d265fe5a6c9d3a7c5665c2624d2)