DATAMONGO-2330 - Apply defaultWriteConcern for bulk operations.

Fixed regression introduced in DATAMONGO-1880.

Original Pull Request: #775

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/DefaultBulkOperations.java

@@ -59,6 +59,7 @@ import lombok.Value;
  * @author Mark Paluch
  * @author Minsu Kim
  * @author Jens Schauder
+ * @author Michail Nikolaev
  * @since 1.9
  */
 class DefaultBulkOperations implements BulkOperations {
@@ -306,6 +307,10 @@ class DefaultBulkOperations implements BulkOperations {
 
 	private BulkWriteResult bulkWriteTo(MongoCollection<Document> collection) {
 
+		if (defaultWriteConcern != null) {
+			collection = collection.withWriteConcern(defaultWriteConcern);
+		}
+
 		return collection.bulkWrite( //
 				models.stream() //
 						.map(this::extractAndMapWriteModel) //