Update git submodules

Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 907d8d6223a7d2f26f6c0d7792a90bc073e961ef
  - Merge "add null check for server HostName/Name/Flavor"
  - add null check for server HostName/Name/Flavor

    add null check for server HostName/Name/Flavor
    maven format file after build failure
    include relationship empty string verification
    add unit test to verify null/empty string
    update empty string validation code

    Issue-ID: SO-2912
    Signed-off-by: Benjamin, Max (mb388a) <mb388a@att.com>
    Change-Id: If308469cd4ec0008a6d1a480641da890d67b4259