Update kafka_wordcount.py

Author: Davies Liu

examples/src/main/python/streaming/kafka_wordcount.py

@@ -39,7 +39,7 @@
 
 if __name__ == "__main__":
     if len(sys.argv) != 3:
-        print >> sys.stderr, "Usage: network_wordcount.py <zk> <topic>"
+        print >> sys.stderr, "Usage: kafka_wordcount.py <zk> <topic>"
         exit(-1)
 
     sc = SparkContext(appName="PythonStreamingKafkaWordCount")