[Streaming][Minor]Fix some error docs in streaming examples

Small changes, please help to review, thanks a lot.

Author: Saisai Shao <saisai.shao@intel.com>

Closes #4837 from jerryshao/doc-fix and squashes the following commits:

545291a [Saisai Shao] Fix some error docs in streaming examples

examples/scala-2.10/src/main/scala/org/apache/spark/examples/streaming/DirectKafkaWordCount.scala

@@ -30,7 +30,8 @@ import org.apache.spark.SparkConf
  *   <topics> is a list of one or more kafka topics to consume from
  *
  * Example:
- *    $ bin/run-example streaming.KafkaWordCount broker1-host:port,broker2-host:port topic1,topic2
+ *    $ bin/run-example streaming.DirectKafkaWordCount broker1-host:port,broker2-host:port \
+ *    topic1,topic2
  */
 object DirectKafkaWordCount {
   def main(args: Array[String]) {

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

@@ -23,7 +23,7 @@
  http://kafka.apache.org/documentation.html#quickstart
 
  and then run the example
-    `$ bin/spark-submit --driver-class-path external/kafka-assembly/target/scala-*/\
+    `$ bin/spark-submit --jars external/kafka-assembly/target/scala-*/\
       spark-streaming-kafka-assembly-*.jar examples/src/main/python/streaming/kafka_wordcount.py \
       localhost:2181 test`
 """

python/pyspark/streaming/kafka.py

@@ -82,7 +82,7 @@ ________________________________________________________________________________
 
   2. Download the JAR of the artifact from Maven Central http://search.maven.org/,
      Group Id = org.apache.spark, Artifact Id = spark-streaming-kafka-assembly, Version = %s.
-     Then, innclude the jar in the spark-submit command as
+     Then, include the jar in the spark-submit command as
 
      $ bin/spark-submit --jars <spark-streaming-kafka-assembly.jar> ...