Update git submodules

Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Remove tempest networking bgpvpn testcases

    JIRA: SDNVPN-230

    This patch removes networking bgpvpn testcases from sdnvpn project.
    The testcases from gambia release and up until now they run by
    functest project inside smoke container. There is no reason to run them
    inside features functest container any more.

    Change-Id: Iae031c17d15822358bfe21448c0d16fa14bc35de
    Signed-off-by: Stamatis Katsaounis <mokats@intracom-telecom.com>