Update git submodules

Update git submodules

* Update docs/submodules/sdnvpn from branch 'stable/fraser'
  - [Bug Fix] Determine the BGP entity owner in ODL Cluster

    In HA deployments is essential to determine which is the ODL
    BGP entity owner and transform that ODL to BGP speaker.
    This is necessary because of this bug [0] in netvirt. So
    we can consider this as a workaround for the testcase_3.

    Note: This patch is dependent on this task resolution [1]
          for master branch.

    Note: This patch works fine in stable/fraser branch.

    [0] https://jira.opendaylight.org/browse/NETVIRT-1308
    [1] https://jira.opnfv.org/browse/SDNVPN-217

    Jira: SDNVPN-214

    Change-Id: I383987e650da45400a3a6437dbdaaea904db9265
    Signed-off-by: Dimitrios Markou <mardim@intracom-telecom.com>