Update git submodules
Update git submodules

* Update plugins/replication from branch 'stable-3.1'
  to 1b171d48e4257e6e0c5189c30b8e2198c5ee1d8e
  - ReplicationTasksStorage: Remove synchronized from list* methods
    
    These synchronized statements were added to make the tests pass.
    However, they have undesirable behavior when considering production
    systems (such as the concern raised in [1]).
    
    [1] https://gerrit-review.googlesource.com/c/plugins/replication/+/280357/comment/757c5227_0de2800d/
    
    Change-Id: I5556ea318aed400eb43c60fdbda41106dd4a17ff
    
GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit,GerritCodeReview/gerrit