Update git submodules

* Update docs/submodules/sdc.git from branch 'master'
  to c39f8ff9e9436d974f9d0021be04b0a925d6745d
  - Minor cleanups for JanusGraphDao
    
    - Fixed typo in a call to `logger.debug`
    - Modified if statement following recommendation from SonarCloud
    
    Issue-ID: SDC-2918
    Signed-off-by: Chris Andre <chris.andre@yoppworks.com>
    Change-Id: I75d50d74703bf7c706b84723bb5d43760b8b7baf
    
1 file changed