Update git submodules

* Update plugins/replication from branch 'master'
  to f0b8c225e060c49072c5a000d5462cb46f5c5b53
  - Distributor: Skip re-fire of already pending tasks
    
    On every cycle the distributor streams all tasks under waiting/ and
    calls fireFromStorage() for each one, which allocates a fresh
    ReplicationState and consolidates it into the pending PushOne for that
    URI. PushOne deduplicates refs, since refBatchesToPush is a Set, but
    its stateMap is a ListMultimap that appends unconditionally. A task
    that stays in waiting/ across cycles therefore grows the pending
    task's notification list by one entry per ref per cycle while adding
    no work at all.
    
    The distributor already snapshots the ref updates carried by pending
    push tasks, in order to prune queue entries whose stored counterpart
    is gone. Each streamed update is removed from that snapshot, leaving
    only the prunable ones behind by the end. Reuse that removal as the
    test, i.e a non-null result means a pending task on this node is already
    holding the update, so re-firing it would append a redundant state. Skip
    it, and let only updates with no pending task reach fireFromStorage().
    Tasks written by another primary are absent from the snapshot and
    continue to be fired, so cluster distribution is unaffected.
    
    This change removes the repeat re-fires when Prune.TRUE rather than
    every possible source of stateMap growth. The startup replay passes
    Prune.FALSE and is deliberately left uncovered. It walks each waiting/
    file exactly once, so no task is fired twice into the same pending push
    and the growth is not reachable there today.
    
    Change-Id: Ib9e77f9cf99cab3d5a6f110f0578ae02eafe9198
    
  - Distributor: Add tests for firing of tasks from storage
    
    Add test coverage to ensure the distributor fires an update which no
    pending task on this node is holding, and the startup replay fires
    unconditionally, without looking at the pending push tasks.
    
    Change-Id: If7fb97cbe9e64dc21dbfb5593541ed2367dad1f5