Merge branch 'stable-3.3' into stable-3.4

* stable-3.3:
  Manage removal of refs
  Use correct placeholders when logging in RevisionReader
  Honour the fetch ref-spec in replication.config
  Log the incoming git refs events for replication
  Fix pull-replication after the removal of Log4J from Gerrit
  Allow replication of refs that point to non-commit objects

Change-Id: I243026135c17cbbe6876f80dd380b1d71fe1d813