Fix yarn/README.md and update docs/running-on-yarn.md

Author: colorant

docs/running-on-yarn.md

@@ -116,7 +116,7 @@ For example:
 
 # Building Spark for Hadoop/YARN 2.2.x
 
-Hadoop 2.2.x users must build Spark and publish it locally. The SBT build process handles Hadoop 2.2.x as a special case. This version of Hadoop has new YARN API changes and depends on a Protobuf version (2.5) that is not compatible with the Akka version (2.0.5) that Spark uses. Therefore, if the Hadoop version (e.g. set through ```SPARK_HADOOP_VERSION```) starts with 2.2.0 or higher then the build process will depend on Akka artifacts distributed by the Spark project compatible with Protobuf 2.5. Furthermore, the build process then uses the directory ```new-yarn``` (instead of ```yarn```), which supports the new YARN API. The build process should seamlessly work out of the box. 
+Hadoop 2.2.x users must build Spark and publish it locally. The SBT build process handles Hadoop 2.2.x as a special case. This version of Hadoop has new YARN API changes and depends on a Protobuf version (2.5) that is not compatible with the Akka version (2.0.5) that Spark uses. Therefore, if the Hadoop version (e.g. set through ```SPARK_HADOOP_VERSION```) starts with 2.2.0 or higher then the build process will depend on Akka artifacts distributed by the Spark project compatible with Protobuf 2.5.
 
 See [Building Spark with Maven](building-with-maven.html) for instructions on how to build Spark using the Maven process.
 

yarn/README.md

@@ -1,7 +1,5 @@
 # YARN DIRECTORY LAYOUT
 
-Hadoop Yarn related code are organized 
-
 Hadoop Yarn related codes are organized in separate modules with layered dependency.
 
  * common : Common codes that will be called into by other modules.