Update git submodules

Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Merge "Stop relying on internal Functest utils"
  - Stop relying on internal Functest utils

    It switches from functest_utils.get_functest_config() to
    config.CONF(). download_url is now hosted in sfc as it's unused by
    Functest.

    The next functions will be considered as part of Functest framework
    (then it must be well covered and documented):
      - ft_utils.execute_command_raise()
      - ft_utils.execute_command()
      - ft_utils.get_parameter_from_yaml()

    Change-Id: I076c6ced430df8387de8eaeac6f3a94d93201b19
    Signed-off-by: Cédric Ollivier <cedric.ollivier@orange.com>