SOLR-4471: Replication occurs even when a slave is already up to date.
  
SOLR-4484: ReplicationHandler#loadReplicationProperties still uses Files rather than the Directory to try and read the replication properties files.

SOLR-4488: Return slave replication details for a master if the master has also acted like a slave.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1449117 13f79535-47bb-0310-9956-ffa450edef68