Update git submodules

* Update plugins/replication from branch 'master'
  - Removed the recommendation for ssh
    
    As discussed many times during the Gerrit conferences and hackathons,
    Git/SSH replication on Gerrit isn't stable enough due to the JSch
    client stack. Removing the recommendation from the documentation
    may help in choosing alternative methods.
    
    Change-Id: I3c8646135999d6cbb99b58d83d42655d25ea23e9