Update git submodules

Update git submodules

* Update docs/submodules/sdnvpn from branch 'master'
  - Use bgvpn-delete and create instead of update

    Testcases 1 and 4 fail because of netvirt bug [1]

    The same functionality is now achieved by using
    bgvpn-delete and bgpvpn-create cli commands instead
    of bgpvpn-update

    [1] https://jira.opendaylight.org/browse/NETVIRT-1067

    Change-Id: Iaba6e06d0f39e356bf364b0640c707b0a83470d7
    Signed-off-by: tomsou <soth@intracom-telecom.com>
    Signed-off-by: Periyasamy Palanisamy <periyasamy.palanisamy@ericsson.com>