Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to 2a278fedffa02f01f9fbc059fc25eab103cd7986
  - Merge "Use base image for SO dockers"
  - Use base image for SO dockers
    
    ONAP now has a specific base image for all containers using Java. This
    commit uses this file instead of creating a base image only for SO.
    
    Issue-ID: SO-2694
    Signed-off-by: Sylvain Desbureaux <sylvain.desbureaux@orange.com>
    Change-Id: I9578e4d5556bd175ad65c6d2f9ce917997651c7a
    
1 file changed