JAVA-2737: Change functional test in SingleServerClusterTest so that it can execute on all supported server versions

Author: jyemin

driver-core/src/test/functional/com/mongodb/connection/SingleServerClusterTest.java

@@ -115,7 +115,7 @@ public void shouldSuccessfullyQueryASecondaryWithPrimaryReadPreference() {
         Connection connection = cluster.getServer(secondary).getConnection();
 
         // when
-        BsonDocument result = connection.command(getDefaultDatabaseName(), new BsonDocument("find", new BsonString(collectionName)),
+        BsonDocument result = connection.command(getDefaultDatabaseName(), new BsonDocument("count", new BsonString(collectionName)),
                 new NoOpFieldNameValidator(), ReadPreference.primary(), new BsonDocumentCodec(), NoOpSessionContext.INSTANCE);
 
         // then