Update git submodules

* Update system-config from branch 'master'
  - Collect haproxy logs via syslog
    
    Haproxy wants to log to syslog (and not stdout for performance reasons,
    see dockerfile/haproxy#3). However there is no
    running syslog in our haproxy container. What we can do is mount in the
    host's /dev/log and have haproxy write to the hosts syslog to get
    logging.
    
    Do this via a docker compose volume bind mount.
    
    Change-Id: Icf4a91c2bc5f5dbb0bfb9d36e7ec0210c6dc4e90