MAPREDUCE-2736 removes start-mapred.sh. We should either update the call to start-mapred to hadoop-yarn/bin/start-all.sh instead or just remove the script since it's deprecated.
Remove unused contrib components dependent on MR1
Fix issues in start-all.sh and stop-all.sh
Modifiy bin/hadoop to point to HADOOP_YARN_HOME
start-all.sh refers incorrectly start-dfs.sh existence for starting start-yarn.sh