Update git submodules

* Update docs/submodules/sdc/sdc-docker-base.git from branch 'master'
  to 639278ba4ddea0ca7402839bc2e49ac70f2e14ef
  - Maven staging plugin removed
    
    Required by global-jjb
    Fixed build of kibana image in passing
    
    Change-Id: Ibbec033c2a1c772a1cadc8b4e7385210e246bb9c
    Issue-ID: SDC-2444
    Signed-off-by: Tomasz Golabek <tomasz.golabek@nokia.com>
    
1 file changed