Ensure collection exists prior to outputting mapReduce results to it

This works around a behavioral change in the 4.4 server's mapReduce
implementation on sharded clusters

JAVA-3555

Author: jyemin

driver-legacy/src/test/functional/com/mongodb/MapReduceTest.java

@@ -151,6 +151,7 @@ public void testMapReduceWithOutputToAnotherDatabase() {
                                                         MapReduceCommand.OutputType.REPLACE,
                                                         new BasicDBObject());
         command.setOutputDB(MR_DATABASE);
+        getClient().getDatabase(MR_DATABASE).createCollection(DEFAULT_COLLECTION);
         MapReduceOutput output = collection.mapReduce(command);