Fix build failure

Author: HeartSaVioR

external/kafka-0-10-sql/src/test/scala/org/apache/spark/sql/kafka010/KafkaSinkSuite.scala

@@ -370,7 +370,7 @@ class KafkaContinuousSinkSuite extends KafkaSinkStreamingSuiteBase {
       iter.foreach(writeTask.write(_))
       writeTask.commit()
     } finally {
-      writeTask.invalidateProducer()
+      writeTask.close()
     }
   }
 }