Update git submodules

* Update docs/submodules/so.git from branch 'master'
  to e4ecd51f615f81fca7567aac583892a32f6a4c3f
  - Merge "Add junit tests for CallbackHandlerService"
  - Add junit tests for CallbackHandlerService
    
    Change-Id: I2f136c2241bdcbfa41a609023c7b3c8eb72eb106
    Issue-ID: SO-1576
    Signed-off-by: Lukasz Muszkieta <lukasz.muszkieta@nokia.com>
    
1 file changed