update YARN docs

docs/running-on-yarn.md

@@ -55,7 +55,7 @@ This would be used to connect to the cluster, write to the dfs and submit jobs t
 
 The command to launch the YARN Client is as follows:
 
-    SPARK_JAR=<SPARK_YAR_FILE> ./run spark.deploy.yarn.Client \
+    SPARK_JAR=<SPARK_YARN_JAR_FILE> ./run spark.deploy.yarn.Client \
       --jar <YOUR_APP_JAR_FILE> \
       --class <APP_MAIN_CLASS> \
       --args <APP_MAIN_ARGUMENTS> \
@@ -68,7 +68,7 @@ The command to launch the YARN Client is as follows:
 
 For example:
 
-    SPARK_JAR=./core/target/spark-core-assembly-{{site.SPARK_VERSION}}.jar ./run spark.deploy.yarn.Client \
+    SPARK_JAR=./yarn/target/spark-yarn-assembly-{{site.SPARK_VERSION}}.jar ./run spark.deploy.yarn.Client \
       --jar examples/target/scala-{{site.SCALA_VERSION}}/spark-examples_{{site.SCALA_VERSION}}-{{site.SPARK_VERSION}}.jar \
       --class spark.examples.SparkPi \
       --args yarn-standalone \