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>
    
diff --git a/docs/submodules/sdc/sdc-docker-base.git b/docs/submodules/sdc/sdc-docker-base.git
index e942426..639278b 160000
--- a/docs/submodules/sdc/sdc-docker-base.git
+++ b/docs/submodules/sdc/sdc-docker-base.git
@@ -1 +1 @@
-Subproject commit e94242606199c0d46a532220d8bad4c96788163c
+Subproject commit 639278ba4ddea0ca7402839bc2e49ac70f2e14ef