Update git submodules

Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 9b78caf92e4a362850a242f04871644dafc20f62
  - Merge "Add ChangeModelVnfBB and"
  - Add ChangeModelVnfBB and

    Add ChangeModelVnfBB and ChangeModelServiceInstanceBB as part of
    fallout for vfmodule replace flow
    Update to execute the ChangeModelVnfBB and ChangeModelServiceInstanceBB
    flows for fallout in vfmodule replace flow
    Update the logic to the ChangeBB  list

    Issue-ID: SO-2976
    Signed-off-by: Benjamin, Max (mb388a) <mb388a@att.com>
    Change-Id: Id50d7ecd2abdd18178fbe2566c247e0c57b54353