Update git submodules

Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Merge "Add/Remove testcase"
  - Add/Remove testcase

    This testcase investigates if communication
    between a group of VMs is interupted upon
    deleteon and creation of VMs inside this group.
    Test case flow:
    3 vms:
    [1] on compute 1,
    [2] on compute 1,
    [3] on compute 2,
    all vms ping each other.

    vm [2] is deleted. Traffic is still flying
    between [1] and [3]. A new [4] vm is added
    to compute 1. Traffic is not interrupted
    and [4] can be reached as well.

    JIRA: SDNVPN-105

    Change-Id: I93a65de2a5df83551e3115fd20b60241cd460e97
    Signed-off-by: panageo2 <panageo@intracom-telecom.com>