YARN-819. ResourceManager and NodeManager should check for a minimum allowed version (Robert Parker via jeagles)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1526665 13f79535-47bb-0310-9956-ffa450edef68
HADOOP-9976. Different versions of avro and avro-maven-plugin (Karthik Kambatla via Sandy Ryza)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1526668 13f79535-47bb-0310-9956-ffa450edef68
svn merge -c 1526688 FIXES: MAPREDUCE-5513. ConcurrentModificationException in JobControl. Contributed by Robert Parker


git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1526702 13f79535-47bb-0310-9956-ffa450edef68
Merging change r1526728 from trunk

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1526731 13f79535-47bb-0310-9956-ffa450edef68