Update DecisionTreeRunner.scala

Author: strat0sphere <stratos.dimopoulos@gmail.com>

Closes #1676 from strat0sphere/patch-1 and squashes the following commits:

044d2fa [strat0sphere] Update DecisionTreeRunner.scala

Author: strat0sphere

examples/src/main/scala/org/apache/spark/examples/mllib/DecisionTreeRunner.scala

@@ -33,7 +33,7 @@ import org.apache.spark.rdd.RDD
 /**
  * An example runner for decision tree. Run with
  * {{{
- * ./bin/spark-example org.apache.spark.examples.mllib.DecisionTreeRunner [options]
+ * ./bin/run-example org.apache.spark.examples.mllib.DecisionTreeRunner [options]
  * }}}
  * If you use it as a template to create your own app, please use `spark-submit` to submit your app.
  */