remove unused import

Author: jimczi

server/src/main/java/org/elasticsearch/search/aggregations/bucket/composite/CompositeAggregator.java

@@ -23,7 +23,6 @@
 import org.apache.lucene.search.CollectionTerminatedException;
 import org.apache.lucene.search.DocIdSet;
 import org.apache.lucene.search.DocIdSetIterator;
-import org.apache.lucene.search.MatchAllDocsQuery;
 import org.apache.lucene.search.Query;
 import org.apache.lucene.search.Scorer;
 import org.apache.lucene.search.Weight;